MetaPost for fonts for epigraphical scripts of India

Hello it's me again. I thought it appropriate to start a separate
thread for this. Please bear with me while I give a brief background
of my project and requirements.

I along with some friends am currently working on developing
encodings/smart_fonts for old epigraphical scripts of India. I think
that encoding a script without a proper font existing for using that
encoding is pointless. The problem is especially with Indic scripts
whose complex nature leads the number of glyphs in a font to be
necessarily more than the number of encoded characters for the script.
So we need to design all the glyphs and the smart font programming to
make it work (using Graphite technology http://graphite.sil.org). We
intend to release these fonts under the OFL for free use by all.

I was aware long ago of the existence of MetaFont but the heavy
mathematical orientation put me off from using it compared to WYSIWYG
tools. OTOH I'm not a hand-wise graphics designer myself (although I
can apply myself to the mathematical portion of it) so I really can't
draw good glyphs myself using a WYSIWYG tool (I'm using High Logic
Font Creator http://www.high-logic.com/font-editor/fontcreator.html),
which is however useful for me for minor corrections, codepoint
mappings and such. Anyhow now I've learnt that MetaFont's raster
output is practically obsolete and we need scalable vector output,
which IIUC MetaPost is the software to turn to.

Now I have image files (JPEG) of old (i.e. 1200+ years old) writings.
As many of them are very complex writings, it would be highly tedious
to calculate the points and such to write a MetaPost program manually.

What I'd like to do is to choose a set of representative glyphs from