Never heard of an SST-50W? Sounds a little like Malkoff's naming convention but I don't believe he makes a P60 drop-in with an SST-50.
Nailbender sells SST-50 and SST-90 dropins (
http://www.candlepowerforums.com/vb/showthread.php?t=282416). I own one of his SST-50's and it puts 550 lumens out the front on 2xCR123A primaries. I have one of his SST-90's in the mail and it'll put out more. He makes them in any tint you want, with any driver you want, with as many modes as you want.
The SST-50 I have now puts out a good amount of heat. In my Surefire 6P, if it's not being held in a hand or used outside in the cold air, it'll be too hot to hold after a couple minutes. I've used it outside on high for 20+ minutes straight with no issue. The SST-90 apparently gets even hotter.
If you already knew about Nailbender's offerings and are actually looking for an SST-50W, then I wish you luck! Remember to post here if you find details on it.