http://www.roland-arranger.com/smf/ Do a search for SRX there... plenty of our members use the -07
If you want a REALLY beefy B3 sound, look around for a used Nord Electro Module. It integrates quite well with the Roland's and blows ANY sampled B out of the water (and it's Rhodes', Clavinet's and Wurlitzer's are to die for as well!).
You can always bring it's audio outputs into the E80's input jacks to integrate it with your speakers...
Personally, I've used the RD series, and though the B3 sounds aren't BAD, you don't get the Leslie effect correct (they use sampled Leslie's, which suck!) and can't ramp up or down properly. Also, if the E80 sounds a bit thin, try using your ears to get the sound you want rather than punching up well known B3 drawbar settings. I find that backing off on the upper drawbars, and the 5 1/3' stop can get a bit of depth back in. It's NOT a Nord, but still (IMO) better than using sampled B3 sounds...