I think the lead guitarist for Abigail Williams has been running a EVH 5150 into an old SUNN O)))) 2X15 for as long as I can remember him being in the band. He swears by the tone
I can say that a guitar -> bass head -> bass cab can sound good, but both the head and modeler need a bit of tweaking. I've experienced, that when you run guiars through bass cabs, things tend to resonate way more frequently than with guitar cabinets, which can totally ruin your sound. Furthermore, i do not think that its possible to get a proper guitar tone through bass cabs, since the speakers are built for a whole other frequency area!
All necrobumping aside, I still have some info here: I currently run a Marshall 1982 guitar cab along with a Marshall 1552 bass cab. It sounds like there's more than one guy playing, and someone's playing bass Seriously, the combo of a bass cab and guitar cab is just awesome. I've never been more pleased with my sound than I am now.
I'm with the positive responses here. You really have to try it and be mindful of what your doing with EQ, and it can be stellar. My current rig is 1xEV 15", 1xPeavey Scorpion 15", and 2xEmi Legend 12", with about 700 watts of bass amp power, and as Loomer said the sound is like layers of sound, like 3D.
I recorded an ep at zing a few years ago, and those dudes were tracking bass with a jcm800 into a 410 and the stereo reamping with a 810. The jcm800 really drove the punch of that bass. There were a lot of mixolydian scales that really shined through the simple guitar parts. As far as with a guitar, I'm interested to check it out. As I type this I'm thinking about picking up a Mesa 215 and running a single rec into it alongside my 5150/orange cabs