I've only ever seen the bent handle structures on eBay sellers - I'm sure some Asian sellers have them, as I think they're Inon, but I don't generally have good leads that way given my location. For example: http://www.ebay.com/itm/Aluminum-ARM-TRAY-...=item41447cd016
I think the difference between them all is a matter of just personal preference and perhaps functional clearance. Do you know the measurements between the arms, and the necessary width for your housing body and any controls? Confirmed attach points for whatever mount locations you have at the bottom? Then it's just a matter of deciding what you think would be more comfortable in use. Also consider the weight of the different arrangements. The bent handles for example look like they require bolted-on ball-tops for arms, while the others just accept balls into the handles (or are integral?). So the flexibility for what you attach to the bent handles is better, since you could put on straight or angled ball heads or something else entirely, although it might take more hardeware in the long run.
I admit I don't really give the handles themselves a lot of thought, as I've got an Ike housing and they come with it, but I don't care for the look of the 'stepped' base (your middle option)...it would be hard to set that down on a camera table to work on the housing on a liveaboard or whatnot. Some sort of flat base seems to make more sense to me (although with domes the balance might still require a towel to keep it upright when set down).