I know of other tomatoes with FEWER seeds (Not quite seedless); They are Legend and Siletz. Both are bred by OSU. They are called Parthenocarpic. So they can grow fruits without need for pollination. This is very useful feature in early spring cold weather and when summer temps are high.

BTW: Siletz and Legend both are OP, not F1 hybrid. OP is actually a stabilized hybrid.

Seysonn

Relatively new (2 seasons only) but there are lots of reviews of them available online from sources other than Burpee and most are mixed. The fruit are clearly small, in the 3-4 oz. range, they aren't completely seed-free if that is important to you, when grown from seed the seeds have a very low germination rate apparently, and the flavor is rated at 5-6 on a scale of 10 (so average). If being relatively seedless (seeds are easy to scoop out from most any variety) then they may meet your needs.

Dave

I've grown Sweet Seedless for a few years now and I'm impressed with it on a number of levels. They come early and hang in there all season long. Flavor is reasonably good. Fruits are mostly in the 8 oz. Range although some are larger or smaller. I have a few dozen plants started again this year and although I've not separated them for sales in the past I'm thinking that this year I might promote this variety by offering it separately.