The idea of controlling an uncontrolled crash in a specific way is kind of bogus. First, no two crashes are created equal. The right answer in one situation is not always the right answer in another. As anecdotal evidence, I went to roll out of a terrible launch off of a hip (a tiny one too... maybe 5') and because of my landing angle, I ended up breaking my collarbone. Second, if you're in the kind of situation in which you're about to be injured, it's pretty unlikely that you'll have time to rationally think about what the right answer is. Usually the thought process is something like "oh shi--*SMASH*." If you've trained yourself to always throw yourself into a roll when you hit one of those "oh shi--" moments, what happens when that's the wrong answer?
Everybody always says not to use your hands on a landing, but you just don't always have a choice. I was watching a crash edit from last season a couple weeks ago (Session 4, 2012: Crash on Vimeo
for reference) and those guys are pretty talented, certainly not complete newbies, and nearly every time they bite it, their hands go straight down to catch themselves. If they can't manage to avoid wrist impact, what chance does someone have who just barely has enough control to make it down the mountain?
Anyway, my point is that the best answer (in my opinion) is to armor way the hell up and not try to focus on crashing in one specific way. If the parts of your body that you'd naturally use to protect yourself are tougher and less prone to injury, that leaves you with more options in a fall. With some beefy wristguards (I like Flexmeters
) it becomes much less likely that you'll break any delicate wrist bones, and turns your hands into usable tools. If you want to go farther you can get pretty much anything else armored up as well.