Crele Old English Game Bantams should be pretty much autosexing.
Barred or Cuckoo of any breed would be about as sexable as Barred Rocks or Dominiques (mostly sexable by color).
You definitely can do sexlinks with bantams. Gold/silver or barred/not-barred would work the same as they do in larger chickens.
Some years ago, I noticed one hatchery started offering sexed bantams of certain breeds only: pretty much the ones where sexlinks or autosexing are possible. (For example, Buff Brahma rooster x Light Brahma hen will give buff daughters and silver-carries-gold sons. So the pullets can be sold as sexed Buff Brahmas.)
One of the easiest, if a hatchery wanted to, would be sexlinked Easter Egger bantams, because there are no color standards for them and because a flock often contains a variety of colors anyway. Just pick through the possible breeders for the right male and female colors, and hatch color-sexable chicks the next year. Raise two small breeder flocks to get the ones you'll breed from in future years.