Two you might consider: Swenson Red has been pretty reliable seeded; its
flavor can win over people who insist on seedless. Petite Jewel has small
berries and mostly seedless; looks like it's coming in with a good crop this
year. Nice in muffins. There's another, larger seedless Swenson variety
that's supposed to be good, but I have not tried it.
I tried the usual northen seedless types here (Canadice, Vanessa, Himrod,
etc.), but too much winter vine burying and frequent late spring frosts
pretty well discouraged me from that direction.