The font is called Eraser Dust. It is on Page 3 of Part 12 (Childish Lettering) of the Script Font ID Guide.

It was a David Rakowski font, which can sometimes be found on shareware/freeware sites, and was also sold by Intecsas.

And yet the client insisted it was called "Chalkboard." Thank you so much, Mike!

There is bound to be some confusion with names, especially with 'shareware/freeware' fonts. David Rakowski digitized a lot of old type designs and re-named them. In turn, other folks may have re-named his fonts.

This is the name used in the 1995 Precision Type Font Reference Guide for the Intecsas font, but I wouldn't bet much that it is the original name.

The typeface Rakowski digitized is called Schooldaze in the Solotype Catalog.

you can find eraser dust here for free.

http://my.execpc.com/~lindgren/page06.html

Your client wasn't wrong, just not exactly right; I have seen it free in the wild as Chalkboard.