I'm with Triple Naitch on this one. because of the elapsed time from the AWA to TNA, it's hard to find a bunch of guys that have done all 5 of the major organizations, but 4/5 is a bit easier. and honestly, you all are way smarter than I am, cuz I could only think of a few.
Mick Foley did ECW, WCW, WWE and TNA.
and that's as far as I got. without looking up any others, Mick was it for me. besides that, I got a bunch of three-sers.
Steiner Brothers did WCW, WWE and TNA. I was unaware they did any ECW stuff but it sounds possible.
Kevin Nash, Scott Hall and Jeff Jarrett did WCW, WWE and TNA, but none of them did ECW that I know about.
RVD, Sabu, Tommy Dreamer and the Dudley Boys did ECW, WWE and TNA, but not WCW I don't think.
so yeah, I suck at this game. what about Jake the Snake Roberts? obviously WWE, he did a little WCW (I remember his feud with Sting in that awful Coal Miner's Glove on a Pole Match), had a quick appearance in ECW and even a tag match there, and then appeared at TNA as a guest referee for a Monster's Ball Match. plus, given his age, I bet he hit AWA as well coming up. but I'm only guessing at this point.