Re: Re: Re: Ok, I'll ask.
http://en.wikipedia.org/wiki/R136a1
From Wiki I found a useful link:-
Abstract of published paper here. probably links to full paper.
Looks like they've done the thinking and that a single massive star is the most likely situation.
http://arxiv.org/abs/1007.3284
One thing about the 150 Msol limit - every limit has its caveats, for example the Eddington Limit where solar radiation pressure theoretically exceeds gravity at the surface of the star - the result is that there is high mass loss from the outer shell of the star, but the core mass can still be exceed the "limit"
http://en.wikipedia.org/wiki/Eddington_limit