I'm a tinkerer (is there a 12-step for that, yet?), and giving this^ idea some more thought I think I'd explore using some of these:
http://www.igus.com/wpck/default.asp...ager&C=US&L=en if all other options fail (and I still wanted to try to use the pedals, but wasn't averse to some permanent modifications)
You could probably clip them into the cups both in-and-outboard, maybe just have to redrill the holes to match an existing metric size clip bearing...then the real mods would be to the pedal shaft, turning it on a lathe so you have a flat contact surface...maybe sourcing some precision spacers to replace the cones. The upside is these bearings are inexpensive, self-lubing, though can be used with lubes as well, easily replaced...probably durable enough for a bicycle pedal application (that's a guess).