Dominink Wujastyk wrote: 

 modern font technology can help.  OpenType includes some "alternates" or "contextual alternates" features that allow the user (or auto-select) to select from multiple versions of a glyph.  But I'm sure you know this.  And it's only certain advanced text-setting programs like TeX that allow one to access such features easily (e.g., through fontspec, manual part IV).

 

I use the FontCreator program from Hi-Logic which allows you to create open type "contextual features".  I've used this feature. I use the professional product which retails for $199.00 but their website says that the Home edition for $79.00 also has this feature (but the home edition cannot be used for commercial purposes).  The program only works on windows.

 

Such questions make me wish to consult Naik's classic work Typography of Devanagari (3 vols, 1971 rev. ed.), but I've never had access to a copy of this rare publication.

 

I have this book. (Unfortunately its in storage in New York). Its been 20 years since I looked at it but I recall it was absolutely fascinating.  As I recall  one volume gives examples of devanagari printing from the earliest printed editions up till fairly modern times (when it was published), another volume  describes the authors ideas for a devanagari typewriter and the third volume focuses on some esoteric ideas of the author.  I can't recall the details.

Harry Spier