Hi Nun,
The Nitto technomatic is a great stem. The comfort and control is amazing. I just got one too and a brooks seat as well. I use Cane Creek SCR 5 brake levers (they must not be used with V brakes! Only with cantis or old style side pulls). They have wide hoods for comfort. If you have STI shifters, they may make a model for those. A 45 cm Nitto drop handlebar is very nice too, especially if wrapped in two layers, with Cinelli cork tape on the bottom and then with cloth tape over the cork.
I have heard great things about Avid Shorty brakes if you want cantilevers. The Sheldon Brown/Harris Cycle site has good recommendations for Shimano long reach side pulls that fit with fenders. Kool Stop brake shoes are supposed to be great and I bought some.
Last, since your largest front chainring is 46, do you use, or have you thought about using, a rear cassette with 11 or 12 teeth? That way you might be less likely to spin out.
aebike.com has a great catalogue and good prices in US.
I built up my 1986 Trek with modern components. One important factor is the year of your Volpe. There are many different measurements and sizes of components. Before shopping for components, if you have not already done this, I suggest starting by asking your LBS to determine which measurements your bike has and which size components you should look for. The compatibility between components and the compatibility between components and frame can be complicated and is very important.