Ohhh yes!!! I have a few. I have a pair of 1 1/4" neodymium disk magnets that have easily held me without a sweat.
Preferably you want NeFeB(aka neodymium or "rare earth") magnets with a second choice of SmCo. Ceramic and Alinco magnets are pretty much useless for this sort of thing.
All i can say is don't hurt yourself w/these things. Speaking from experience thye can cause some pretty bad injuries whrn they stick to stuff they're not suffosed to.
Suppliers:
http://www.wondermagnets.com/cgi-bin...manent_Magnets
http://www.allelectronics.com/cgi-bi...370&type=store
As far as isolating them from stuff that shouldn't be too much of a problem. Just put some thin steel sheet against all the unused surfaces and isolate that from the rest of the robot with some Aluminum or Plexi. I have never noticed a problem with RF interference either.
If you want an idea of the strength of neo magnets then bust open an old hardrive and it will contain some very small ones, which actuate the head assembly. (but not too old. If its a 3.5" then it will have them. any older and it may or may not.)
Instead of using them to attach to the bar, I see them as having greater applications moving goals. Simple: Powerful magnet + pnumatic detacher = easy goal dragger. This solves the problem of having nothing to grab onto. It also solves the problem or precisely aligning a mechanism w/ the goal.