They say Critical Mass yields pretty good, and finishes in like 45 days. I've never tried it, but those that have seem to like it..
Chimera's Mental Floss is a huge yielder, 900 grams per m2, and flowers in 55-65 days, only place I have seen it was Hemp Depot.
Never grew it (yet), but got to smoke it a few times, it was actually quite nice. Had a really nice sativa high, no couch lock whatsoever.