Well...maybe only in spirit, not actuality. But I keep finding myself wanting to convert all my RPGs to some version of the same basic system (namely, B/X).
I mean it's hard not to...for any game where combat is a major factor, I find the B/X combat system to be pretty darn good. Recently, I was considering how easy it might be to convert Shadow Run to a B/X equivalent...after all, what is Shadow Run but a party of fantasy characters going on adventures in hopes of scoring ca$h. It's the same damn thing...except with guns and cyberware.
Ugh...I'm as bad as the brain trust behind D20 (or GURPS, for that matter). Not every role-playing setting requires the same system, and definitely not every system is a good fit for every setting. For example, I would NEVER try to make a B/X equivalent of Vampire the Masquerade...that's just ridiculous!
[well, probably never...I try never to say "never"]
But there are many games that just seem to be begging for a B/X-style streamlining. Shadow Run (i.e. "fantasy cyberpunk) is definitely one of them. The superhero genre is another. So is the space opera setting. So is the 1930's pulp adventure setting. Maybe even Rifts (i.e. "fantasy apocalypse").
Maybe I should come up with a list of games that I see (in my mind's eye) as "convertible," just to see what the common denominator of all of 'em are. Maybe I'm just in a semi-exhausted trance-like state right now and not thinking clearly.