I'm wanting to perform a build up of my ~94 Bianchi Nuova Alloro Special and would appreciate some help in figuring out what I can and (more importantly) can't put on the bike. I have a completely mixed group now and want to go to a mostly single campy or possibly shimano group.

Here is what I have:
shimano 105 shifters on downtube (maybe go to STI or stay with DT)
Modolo America breaks and levers (I love these, but would consider replacing with sti)
shimano 105 RD (replace)
compy FD (clamp on, no idea of the model)
Bianchi cranks (2 ring) (These are nice, so I can just upgrade the rings or the whole thing)
UNK BB (has bianchi engraved bolts into it) (rebuild or replace it? Italian or English?)
6 spd cassette (should I go 8/9 or 10 ring, I know I need to open up the frame, but is 10 to big?)

Wheels/hubs will be separate.

I hope to find all of these parts on e-bay or local in new/good used condition. This will be my winter project, so I have some time. Any and all info would be fantastic.