I am looking into buying a used Canon 70-200 2.8L lens and was told "might be a back-focusing issue with that camera/lens combo."

Any 10D users with this lens?

When I initially got my 10D last year I discovered a back focus problem with it and an EF 24/2.8. I then tested my 10D against a whole arsenal of lenses owned by my coworker. One of them was the 70-200/2.8L non-IS. It, too, back focused. I sent my 10D to Irvine. When I got it back, I could not determine whether or not they actually recalibrated it. I had already exchanged the 24/2.8 for a 17-40 and was never able to retest against the 70-200.

I've, since then, acquired a 80-200/2.8L and it focuses fine along with all my other lenses, except my 50/1.8 Mk I, which front focuses a teeny bit.

I really doubt there's a systemic focusing issue with the 10D and 70-200 combo, my experiences notwithstanding.