I've been playing around with stereo, in two ways:
1. I've done some recent recordings where I played fretless bass and tracked it twice, into two channels. I played on each track seperately, so there are slight variations in the intonation between the two tracks--which gives it a natural chorus effect. Then I panned one track 70% left and the other 70% right. It sounds much more expansive than a single bass track. I got the idea from reading about how Billy Gibbons from ZZ Top gets his massive guitar sound.
2. I've been experimenting with Rick-O-Sound on my newly acquired Ibanez Rickenbacker 4003 copy. Rick-O-Sound is a stereo output that sends one pickup left and one pickup right. Using a splitter cable, I've been sending the bridge pickup to my usual rig (Demeter 400D w/ Epifani 2x10 cab) and the neck pickup to a Hartke 1x12 combo) and it sounds huge (these are stacked, not split on different sides of a stage--the Hartke on the floor, the Epifani above it on a stand). Next I think I'm going to replace the Hartke with a 1x15 combo--maybe a Fender Rumble 200. I haven't recorded with the Rick yet, but I'm curious to try using Rick-O-Sound to send each pickup to a different track and then do different EQing and effects on each track and pan them.