MGS in California have a 3 into 1 for sale although they have no dyno numbers for it. I don't know how good it is or what kind of numbers you might expect as nobody I know of has it. You can see it on their website. Looks like the TORs until they branch into the single can. The MGS folks claim that it sounds more like a sportbike than a cruiser.
Thanks for the information but none of these pipes take my fancy. I love the look of the R3 but not that keen on the pipes. I have always wanted 3 into 1's for the R3, I had them on the old GT750 some 25 years ago and really liked the look. If you guys can find out anymore please let me know.