What didn't you like about the Duncans? I used the SPB-2 Hot for awhile, so I have some experience. I've also used the DiMarzio Model P, so if I know what you didn't like about the Duncans maybe I can make a semi-educated recommendation.
Personally, I thought the SPB-2 was just too phat in the low mids for the band I was in. It was somewhat boomy. I also thought it sounded too smooth, as I like some grit in the tone. I swapped it out for a Lindy Fralin, which I love. The Fralin has similar output, more cutting high end with the tone on full, and a slightly gritty texture. I'd call it "aggressive vintage."
The G&L MFD in my SB-2 has similar crunch, but with monstrous output and a thicker, heavier tone overall. It can sound very gnarly/snarly, which is a good thing! I think the DiMarzio is similar to the G&L, but with less vintage warmth and character. It's great in a hard rock band mix, but for overall use I prefer the Fralin or G&L.
You should be able to get the G&L pickup from a G&L dealer. Try
www.guitarmannyc.com.