What do you mean by "bust"?
A really good wrestler that never was, anywhere, at any time? Or, just not successful in say...the WWE/F?
I mean, take for example...Lex Luger. He was the...erm...Total Package. Great look. Before he was in the motorcycle accident, he could be very carryable to great matches, and he could talk at an above average level. Was given the ball a number of times and it just never worked. I mean, many people would call him a bust. Is he though? I don't know. Some guys just don't connect with the crowd to the level of their push or what they should be. Luger was one of those guys. I don't know if he's a "bust" though...he had a really long career, always at or near the top, was involved in a lot of big matches and moments (good ones, too)...just never drew dime.
You look at some recent WWE guys, like Ken Kennedy, MVP, Carlito, Shelton Benjamin...all had what you look for in some regard, all got pushed at some point, all just never really connected. I guess those guys could be considered busts. Ken Doane was one of the hottest "prospects" in the WWE in the 2000's. Brent Albright. Bobby Lashley.
If you use the "injury" excuse as a label for bust (say...the Ki-Jana Carter paradox)...Magnum TA...or pregnancy...Awesome Kong in the WWE...or drug use (Charles Rogers paradox) Art Barr or Gino Hernandez.
Muhammad Hassan had an epic amount of potential. Bad timing. Chris Masters never got a real chance. Pretty Paul Roma looked the part, got his chances, but was a nobody.
Foreigners that just can't get over in the US like Sin Cara.
I'm just not certain of the term "bust" in the context of wrestling.