Wolfman,
Unless you have a particular need for half-axles, such as having a dropped floor at the axle location, you might find that a complete torsion axle with the full cross tube might make life a whole lot easier for you. It would eliminate the issues of half-axle alignment and having to provide adequate mounts and frame cross members. Half-axles are just trickier to deal with.
The Dexter axle website has some useful information regarding ride height:
http://i.b5z.net/i/u/1080235/f/Torflex_ ... n_4-04.pdf Look for the #9 Torflex axles. The wheel charts for the #9 only show ride heights for wheels up to 13" diameter....add another 1" ride height if you go with 14" wheels....this is not exact but close enough. If ordering an axle from Dexter Axle there will be a specification sheet you will need to fill out and the axle will be custom made to your desires.
From what I'm seeing on the internet, it appears that the Reliable Rubber axles are handled pretty much by Northern Tool. The half-axles that you were asking about appear to be available only in the 45 degree down start angle. Their full axles are available in various other start angle settings. When you look at their prices remember that you have to buy two hub+bearings assemblies as the Reliable axles don't seem to be priced with hubs.
Another option is to use the adjustable start angle axle ....Flexiride. Several members on this forum have used this axle and appear to be satisfied with it's performance. Available from
http://www.trailerpart.com/ as full axles or half-axles. They typically cost a bit more than the Dexter axles, a lot depends on who can get you a Dexter axle locally.
From what I've noticed....totally unscientific....Dexter probably is used by the torsion axle builders on this forum maybe 10:1 over the Flexiride. Perhaps it's the cost, a part of it is the supply chain to actually get an axle in hand. Dexter does a better job there. The Flexiride is adjustable and a little more sophisticated in design, but has fewer dealers.
You need to figure out what your trailer will weigh... a good estimate....that's the first place to start.
Hope this helps some.