First post of this thread:
http://www.haytalk.com/forums/topic/17858-the-hay-handling-thread-bundlers-bale-wagons-stackers-accumulators-coming/
I'll expand to cover the 4 you can get in north america.
Bale bandit - longer bales required 42" I think unless you modify it. 21 bales. Steel bands. Early models can be challenging without the updates. I've read the latest ones perform very well. Lots of options including a handy one I think, its quickly convertable from towed to ground pickup.
Bale Baron - Short bales 34", 21 bale bundles. Big bales twine and knotters. Are known as being quite reliable. Tow behind and pickup models, self containted hydraulics and engine available.
Tie-hog- Just entering the market, they are 10 bale bundles normally but can set any length, farmer built machine based on large square baler, has run for years precommercial. Very fast compared to the hydraulic units. Rare, won't see one likely for a few years. Short bales.
Arcusin - B14 or C14, 14 bale twine tied bundle but you can make shorter for wrapping individually. Upright machine, reportedly one of the best built machines out there. Very expensive in Canada/US due to import. Quite rare really. Only available as pickup model. Self contained pto driven hydraulics. Mid length bales, I think 36-38".