I went through the similar dilemma. I had a Cannondale that got a pronounced bottom bracket creak due to age. In looking to replace it, I began to consider a steel frame. I was looking for a complete new bike and realized that my old Bianchi with down tube shifters had recessed brake bolts. Long story short, I just got a new gruppo and put it on the Bianchi. Plus some wheels off craigslist. Here is my '84 Bianchi Specialissima with a '99 Campy Carbon Gruppo. Only thing is that I kept the original cranks as the bottom bracket I got was the wrong size. The front derailleur is the newer one now also.
Something to consider if you’re attached to your current frame.
-W
