ORIGINAL: Blacksheep
I second the motion for CNA. I managed to get through five turns of that monster in my pre-pc days, and I look at it as one of my finest gaming achievements. The logistics lend themselve to a computer model not to mention the A2A combat (which took days in itself to resolve). Probably will never see it but I can dream.
Looks like lots of people had the same idea about CNA. I am not sure it would make a very good computer wargame, though.
Like many similar monsters, CNA implies a lot of small decisions by the players throughout the turn sequence. Unless you totally rework the combat and movement system, you won't be able to translate this into a WITP-like computer game: you'd end up with an incredible click-fest. The turn sequence also has a lot of player interaction, which complicates PBEM.
What might work would be a Vassal-like system, that would keep all the game files on one's machine (and therefore reduce the playing space), help with die rolls and resolution, and (perhaps?) could be played PBC (play by chat), in interactive sessions.
I have been toying with this idea for a long time, never really took the time to explore it in details, but I believe that would be the way to play "old wargames" again.
On the other hand, the design has lots of very interesting ideas, which could be used by computer games. For what I've seen, most computer wargames sort of "evolved" from ASL-like systems, where you get large scale result by agregating small scale figures. Many paper wargames followed a different, top down, route to modelling, that probably lends itself better to AI programming, and would most certaintly result in games with a very different feel than the ones we play now.
Francois