Quoted from 1974DeltaQueen:
That repair corner is the best idea I've heard yet. I had one pin break down twice played great before I loaded it on the trailer. Thanks to Pingeezer for his help and the knowledge I gained.
A repair corner is a good idea in theory, however, stocking the right parts for a large variety of games and game systems might be a little tough.
I have parts, electronic components, connectors, and various tools in order to work on games from 7 different manufactures and 16 different game systems. I need to keep quite a lot of stuff in stock to work on all those. I imagine a repair corner would need to be prepared to handle double that. And that is quite a lot of parts and expertise that would need to be on-hand. A few people would basically have to uproot a decent chunk of their repair shop.
Then, diagnostic equipment and test rigs might be necessary to help diagnose board issues.
Not to say that it wouldn't be feasible, but just that it would be a challenging endeavor.