Tried the trick from Jeff's Talkbass thread with a thick sock under the strings at the bridge and plucking hard up by the fretboard. Really cool!
Ran it through a 810 cab from Amplitube to get rid of the DI-ness (I know you don't generally mic speakers when recording double bass, it just sounded better). Added a lopass filter and a peak of EQ to try and bring out some pseudo-woody midrange at ~1200 Hz (any higher and the "electricity" of the bass became too obvious). Finally added a little room verb to make it sound more like it was recorded with a condenser.
I tried using an expander like you said Karyn, for further diminishing the sustain, but they all started distorting before I could get the effect I was trying for. So I used iZotope Alloy's Transient Designer to do it (though I couldn't go overboard with that either before the sound got messed up...
Think it turned out pretty nice and I think might fool some people within the context of a mix:
https://www.dropbox.com/s/wfjnutu9ngv0jtj/Fauxbass.mp3 Tips on how I can improve this further are welcome!
Sven