Just got my hands on a 1989 vintage Trek 1200 which has all Shimano 105 components - brakes, derailleurs, cranks, hubs. Nice bike, really looks like it was never used - but the frame is way too small for me. Someone suggested transferring all of the parts to a new(er) frame of the right size. Is there anything that I need to look out for in doing this? How have the Shimano 105 derailleurs changed since 1989? The Trek has downtube shifters - can I switch over to integrated brake/shifters? What do I need to know about the bottom bracket? Dropout spacing? Any other "gotchas" that would make this difficult or could trip me up? Front derailleur mounting?
I tried posting this over in Classic and Vintage but we quickly got off topic and never got to the specifics of how to do this so apologies if this is in the wrong place.

I just had all my parts switched over to a new frame. Ideally, you should take your bike to a trustworthy mechanic, like I did, and have it evaluated. It is otherwise difficult to advise you without seeing the bike.

Yeh, thanks, but I've always done all of my own work - worked briefly at a bike shop many many years ago. I was really looking for more pointed advice such as "watch out for xyz, it needs to be ______".

I cant believe the year I graduated HS is now considered vintage......I am going the bathroom and drown myself now..

This bike was never ridden - I know the original owner, he bought it on a whim, and I doubt if it even has one mile on it.

I have a set of perfect Shimano 600 from 95? I'll put on a road frame someday.
My mtb runs several old racing components.
The bike was never raced, I'm the main contributer to the demise of the gear.
1991 Ritchey logic headset.
1990's Mavic rim on a DeoreDX hub\Shimano cogset.
A NOS mid 90's Ritchey quill stem.
All else is new.

The Ritchey components will last, the Shimano will be toast by the end of summer.

My 2c worth, I had a similar vintage bike with 7 speed shimano stuff. He had a set of RSX 7 speed STI's fitted, they looked nice & worked a treat. You may still find these around on ebay or something. They looked well made, alloy, felt better made than new 105 stuff (I'm sure this isn't so).

Ok, now my 2 cents.

1. I would search Ebay for a good condition frame of the same era that is the right size, and transfer the components. I wouldn't buy a brand new frame, since the components are 16yo, even though they are in great condition.

2. I would sell the bike to someone else, or give it to a loved one, and just go out and buy a differant bike with the right size frame to begin with.