I don't have a squeak here either, just the vibration.
I've been stuck in A LOT of stop-go 10mph traffic lately and as a result haven't had a chance to even see if this was still happening to my car, till last night.
Pulling out of a standstill in traffic on the highway I quickly got the car from 2nd gear 10mph up to 50-60 in 5th, I short shifted 4-5 but let it pull pretty good in 3, and ended up with the vibration coming back. It was gone by the time I got home.
I think I'll have to drop my car at my fathers and tell to rip on it into work when it's cold, that way he should be able to duplicate it.