We've adopted a tomato called Texas Wild. Something about the name just made us think of cowboys and riding off into the sunset. But please don't let this be your motivation for adopting a rare variety. There aren't that many cowboy-themed veg varieties on the list.
You could choose the Walla Walla Sweet (onion), the Long Green Buddha (pepper) or the Lazy Housewife (climbing French bean). At £15, it's a snip.