Found these on Pacific Poker, whilst not actually HU I figure they're more relevant here than elsewhere.

These must be +EV for anyone familiar with HU play. Its a 3 person, winner take all tourney, structure the same as HU but with an extra player. Slightly higher rake ($10 + 0.70 is what I've been playing), but it works out to be almost like having a complete buyin worth of overlay. Now obviously this is just the low buyins I've been playing, but generally folks cant wait to knock themselves out, or play a real loose/weak/passive style game. At worst you end up HU with a 1:2 chip deficit, but generally higher if not a chip lead, and from then you just play standard HU game.

Not sure its very $ev for your time, but they're fun .