This one looks promising, as it's supposed to be very sweet, and have fruit as large as regular cherries. It's also very cold-hardy (to zone 3), and it's self-fertile. Said to produce 10-15lbs of fruit. It says it's Prunus fruticosa x Prunus cerasus, in which case I'm surprised it's not more sour than a sour cherry (sour cherries are supposed to be a cross between Prunus fruticosa and sweet cherries, I believe).
The same website mentions several other kinds of bush cherries.
Location: SW Idaho, USA
USDA hardiness zone: 6
Elevation: 2,260 feet Profile post