LOL! timely post(and not unexpected mind you!).

FWIW, I say go for a 7D.

I have no idea on how well your current lenses work, but you also haven't specified a particular genre of photography that you concentrate on either.

if you do a lot of landscapes, then I would suggest a 7D and Sigma 10-20 f/4-5.6.
If you do a lot of portraits.. I have no idea on what works and what doesn't work in Canon world, but I'm sure there are there are some good quality cheap lenses that can produce high quality portraits.. if not a Tammy 28-75/2.8 or 17-50/2.8(or Sigma equivalent) will work well on any camera

Second hand 50D plus second hand 17-55 maybe??

as far as I can tell from all the publicity, the 60D is a downgraded body type(level) compared to the 50D.. so the 7D would make more sense in the long run, catering to any as yet unseen future needs for a longer period.
I think if you want to upgrade the camera body, then you really should be looking top get one with a lot more features/advantages than one you already have.

I think, to get a more accurate recommendation from someone that may have different priorities to yours, you should specify what your preferred photographic genres are.