One solution to the crankset issue is to use Campagnolo 10-speed shifters with Shimano 8-speed cassette and derailleur. This combination shifts very nicely. The 8-speed chain is wide enough that it plays nicely with the older chainring spacing on your original cranks. The Campagnolo front shifter is ratcheting rather than indexed so it also plays nicely with the older chainring spacing. I would guess that a complete Campagnolo 8-speed system would have the same advantages.
Hopefully others will chime in here with other combinations that work.
Brent