Harley and Mustang both make a touring seat for the sportster and I'm sure there are more that I'm forgetting about. They won't be quite as big as the seats on the touring bikes but then the Sportster isn't as big either.
Can a large passanger seat be put on a Sportster? The ones like on the big touring bikes?
How large are we talking here?
Seriously, though...
Yes, you can put a bigger pillion on the Sporty, but it will not be as large as you'll find on the touring bikes. The bike simply isn't as large as the tourers.
Corbin, Mustang, Saddleman seem popular, as is the HD Sundowner.
I Have a touring seat, They have the same style at www.steelthunder.cc it helps on long trips with my girl but it still bothers her a bit when we go for too long. Its "Comfyer" then the other seats weve seen. I just lucked out when I bought the bike it came with it.
Check out the Harley Pillowtop. High comfort for rider and passenger, looks good, and reasonably priced. Comfort is a decision you make. Take the path less traveled and ride with a smile.
I'm running the Ultima Shootout style 2-up full gel seat. I forget how wide the passenger portion of the seat is....I think it is around 8 or 10"s wide. I know my ex-GF commented about how much better it was than the cheap little add on stock 4" wide passenger pillion.