I like the A. I think the B and the D are going to be too narrow in comparison to other uppercase letters. Other than that, I'd need to see more letters to really give feedback.

If you're using Gimp on Linux, check out fontforge (http://fontforge.sourceforge.net/) -- it's a free font creation tool, and you can construct your glyphs the same way -- with a guideline and a brush.

Thanks.
I'm trying to keep the thing roughly monospaced, in that the letters will be roughly half as wide as the height of the line (hence the lower case circles), so I was actually thinking of reworking the A so the right leg was on a steeper angle, thereby making it thinner, but, as you said, it looks really nice as is. Which upper cases look best with the lower cases?

I'm a little stuck on e. Would you recommend a circle with a section taken out and a line added, or a circle with a transfer to a wide ellipse (like how the a has a transfer from ellipse to circle back to ellipse to blunt the end and the d does a backwards transfer to the ascender [if that's unclear, I'm basically just using the fact that curves are parallel where they meet to switch from one path to another]), pulling out to a horizontal line at the bottom of the ellipse (like how I went from circle to vertical on the b), or something else entirely? (yes, I user "or" thrice, but would you have understood what I was saying otherwise?)

I am a bit confused as to why you are making it in a pixelbased application like the Gimp. I would use a true vector app, to be honest.

Because I have it and know how to use it (kind of).