Corbin Seat
I'm lucky enough to live close enough to the Corbin factory to make it easy to go there to have a custom seat made. I had one on my last bike and loved it, so I got one for the SV too.
I'm short, so it was supposed to help lower the bike a bit. It is lower, but it's also wider, so there's not a lot of overall gain in terms of getting my feet flatter on the ground. But it's still a cool seat. I also had them build it forward for me, so I'm no longer floating around somewhere in front of where butts are supposed to fit into the seat.
We got in to Corbin a bit late - it was almost 10am - and thus were almost last in line. The only people that came in later than us were from Missouri (where apparently they don't have any curvy roads). Due to our lateness, we didn't get out of there until about 4pm, by which time the winds had picked up to semi-terrifying levels on the roads north of Hollister. (It was blowing hard enough that the bikes were leaned to the side like they were cornering hard, just to go straight.)
If you're having them make a custom seat, be picky. They'll let you take it out and ride around to test the shape. Take it out on the road and try to ride in as normal a position as possible.
They don't make a replacement passenger seat for the SV, but I had them recover the stock one to match the front. It wasn't exactly cheap (about $250 for the front and $100 for recovering the back) but I think it looks cool.
The finished seats. Apart from being comfortable, I think they look nifty.
We left immediately from Corbin to ride to Portland, OR via 101 and a number of backroads. Although it was a great trip, I strongly advise against using a long trip to break in a Corbin seat. It takes about 1000-1500 miles for the (quite firm) foam to properly mold to your butt, and I think that's probably better done as shorter rides, where you're not in the saddle for more than a couple of hours. A ten-hour day (or longer) on a seat that's not yet broken in is not the happiest tactile experience. Once it breaks in, though, it kicks ass (in a good way).