Triple front mech - which one?!

[CC Rider]

I am swapping my winter hack to a new frame and have a Shimano triple front ring 52-42-30. Unfortunately the downtube on the new frame is larger (31.8mm) so I need to replace the front mech. While I'm at it, I thought it might be worth upgrading from the budget Shimano mech I have been using.
Could I use a Campag mech? There are plenty of Veloce or Race options on ebay; any thoughts on which would work better? .... or should I go with Shimano 105 or Ultegra? .... or something else?!
The reason for considering Campag is that the hubs are Campag wide flange and the idea of gradually moving other parts to Campag appeals.

 

[bontybonty]

3x9 or 3x10
The 10 sped chain is 1.2mm narrower
3x9 I'd recommend xtr 970
Likely will also shift 10 speed
Comes with shims

 

[bontybonty]

This beautiful works like silk
Needs 9 speed chain

 

[CC Rider]

I should have said - it's a road bike and currently on 6 speed but thinking of going up to 8/9 maybe. I'm using downtube friction levers so not too pernickity .... will MTB parts work?
Also working on a limited budget ..... those XTR bits are indeed lovely but a bit out of range