I don't think I've ever come across one that wasn't exactly the same. Perhaps stretched a bit horizontally or vertically, but hardly ever matching the style and personality of the font it's part of.

From Wikipedia:
The mark looks like a stylised lower-case "e" and its shape is precisely defined by an EU directive.
If it was styled to match the font it technically stops being an official estimated sign and becomes just another 'e'.
See also CE marking
In order to be useful, the sign has to correspond to the EU specifications, since its use is precisely in the domain of EU packaging regulations.
Some years ago, I created a FontLab source containing just this glyph, carefully following the EU specifications, which is freely available for download.
It is worth putting this in your fonts because it will enable some European customers to check a box in their procurement requirements, even though they could get the glyph from numerous other sources.
Ryan, what you propose may or may not be 'just another e'. But one thing it definitely is not is an EU estimated symbol.
Some people try to draw a parallel between this symbol and the euro sign, which also has an official reference form documented by the EU. But the difference is that the estimated symbol is legally required to have the specified form in use, and if a company were to use your Antique Olive Nord form in their packaging they could run afoul of trade regulations.
Not just a European company - any company that wants to sell in Europe. And when you're making a font do you really want to limit your users to makers of non-European products? And really, do you think somebody's going to choose your font because your Estimated sign looks cool?
Don't rebel at the expense of your users - they're on your side, but they don't want to pay for your desire for self-expression. And this sort of humility is exactly what Design -as opposed to Art- is about. You want to make a difference? The stupid Estimated symbol is the last place to try that. Take a shot at the lc "el" instead - it's the village idiot of the Latin alphabet.
hhp
I don’t see anything wrong with applying a slight veneer of styling to this glyph, as long as it’s in keeping with the spirit of the EU directive. After all, think of the Euro!
Besides, package designers generally make it relatively large in relation to the accompanying text, so that it looks like the symbol it’s supposed to be, not just a big /e — and also because they have to bump up its size, as it’s a “didone” with hairlines that are in danger of disappearing.
There may well also be some regulation about its mandatory size. In that case, maybe the didone effect is intentional, because it suggests to designers that they increase its size?!
It’s a difficult design—a symbol that is supposed to look like a symbol, and yet also suggest “e” for estimated and possibly “e” for European.
Here’s the symbol in Myriad and my Richler typeface, at same size as the type, and enlarged:

Nick, I don't think this is a "spirit" thing. If some bureaucrat -or opportunist- notices the deviation from the "letter of the law" then you're in real trouble.
As John said, a comparison with the Euro doesn't go very far (although one can make an argument for including an "official" one on the side).
hhp
Would the type designer really be the one in trouble though?
Possibly. Consider, a company purchases from you a license to a font that supports the estimated character. They use the font, and then get into legal or regulatory difficulties that cost them money. They are very likely to come looking for compensation.
I suppose that this sign, then, needs to be treated as a logotype, similarly to other things that appear on packaging, such as the symbols for RoHS compliance, CSA and UL approval, FCC authorization, and so on. Which makes me wonder if it even belongs in any normal fon, as opposed to a special font of useful logotypes - but it was assigned a Unicode point, which, of course, leads me to fear that some types would include variant forms due to simple ignorance rather than rebellion.
Yes, it is something like a logotype. The only variation I make when including it in fonts is to scale the outline so that it corresponds to the height of the lining numerals, since it will almost always be used in concert with them. I don't think it is something that needs to be in every font, and the reason it has become relatively common is that it was included in the WGL4 set, which was adopted as a basis for a lot of pan-European OT fonts.
“This letter shall have the form shown in the drawing contained in section 3 of Annex II to Directive 71/316/EEC.”
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CONSLEG:1971L0316:...
I cannot recall seeing these letter identifiers (p2).
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2007:073:0010...
Tim
This is the first font-related issue I’ve come across where I could imagine there may be some legal culpability on the part of a foundry, that the usual EULA disclaimers might not cover.
I can see that I’ve made a mistake by styling the Estimate symbol in Richler, but fortunately this hasn’t been released yet.
I wouldn’t say that this attention to detail is self-serving and precious though, Chris.
One is catering to the package designer who is creating a design of subtle stylistic consistency, and loth to destroy it with a bloody great clumsy generic bureacratic blot—necessary though that identification may be for the consumer.
Actually, the consumer is the last person for whom the symbol is necessary. Essentially, this symbol is used to identify a tolerance of inexactitude in weight or quantity, within which a company may trade. It avoids the possibility of formal complaint on the part of the consumer whose purchase turns out to be less than the specified quantity or weight, so long as it is within the allowed tolerance of the estimated amount specified on the package.
Anyway, everyone feel free to use the estimated symbol outline that I provide, and use the time you save not making your own to do something truly creative (or rebellious).
Captured from web.archive.org on 21 Oct 2013. view this capture