Anybody out there know of some kind of VST software for PC's (or hardware though I'd prefer software), that can take your original voice and change the tonal characteristics to make it naturally (that's really important) sound like someone else? (same sex, not trying for the sex change...

What I'm after is the equivalent of all of the guys in my band singing together. Of course I can multi-track, harmonize, etc but all voices still sound like me (because it is me

Unfortunately conflicting schedules have made it pretty difficult to get the true different voices tracked. And paid is fine. I'm not looking for freebies here, I need something exceptional that allows me fast turnaround. Any ideas on software/hardware I should check out?
Thanks again for your help as always. - Roger Gilpin