Another user in favor of the XIT404 tripod. I use one for my L&M video housing and it works fine.
I tried the more conventional tripod/ball head combo from TLC (Technical Lighting Control) and it failed miserably.
The difference is the spread out mounting points for the legs under the XIT404 base vs the single point mounting for the TLC.
The single point is fine for above water use, but isn't stable at all under water unless you have a very heavy housing; even then it will be more or less overloaded. Also the single point attachment and swivel head design makes it too tall - it is impossible to get the assembly as low on the sand as with a flat base.
If you spread the legs on the XIT404 base, it will get the housing flat on the sand. You can't get a stable low position with a single point tripod; it will tend to flop over. How do I know this? Been there, tried that. Won't go back.... Anyone want a TLC cheap 
Tom
Edit: Gates also makes a tripod similar to the XIT404. I haven't used it, but I have seen it in use; it seems to work fine and the user gave it good comments.
Edited by wydeangle, 23 March 2013 - 05:52 AM.