I posted this yesterday in the Rohbushin thread, but it got swallowed up by a flame war. So I'll post it in the actual Rankurusu thread.
How does Rankurusu do against Rohbushin? Seems like the Cell can come in on a resisted Mach/Drain Punch and take the hit fairly well with his bulk. Because Rankurusu is actually even slower than Roh, the Clown's Payback won't do as much damage, so he'll either switch out or Bulk Up and hope he doesn't get a Psychic/Psycho Shock to the face. Meanwhile, Rank can Recover off the damage he took from switching in. I guess this can lure in T-tar, and you can do whatever you want from there. The only truly terrible thing that I can imagine happening is that your opponent switches in a Shanderaa, but you might be able to Shadow Ball her or predict her arrival and switch in something of your own to counter back.
Then again, this is me going off of speculation and forum talk without any number crunching.