I know 661 do wrist guards, never broken my Scaphoid though, so no idea if they are any good or not.

I've broken both my scaphoid's at different times, and a complete bugger it is too.  I've regained full movement in both, although it has taken a long while.  The 661 Race Brace will help, but you'd probably be better off with a proper medical one, i dare say it'll be cheaper.  Were you given anything? Ive got a brown hospital one that i used?

It took me about a year to get full movement back with no pain, but i started riding gently after about 8weeks.

Rootes

i pulled some tendon or something in my wrist last year and now use my snowboard wrist guards. theyre ace and really do support your wrist well, made by 'red' i think thyere a sub-company of burton. 

theyre good as there is a pretty solid support plate down the top of your arm(as well as a shorter one underneath) so it supports your wrist if it gets bent backwards.  I use these wrist guards even now my wrist is better as it makes my arms feel stronger! though i will say on longer tracks they'll increase arm pump, like this weekend at rheola i couldnt use them.

it would probably also be a good idea to use a powerball (gently) to get the strength back.

Broke mine a few years back, in a cast for 4 weeks and was riding after about 2 weeks in the cast, once the cast was off, I had full movement and everything, but my wrist would give way over small bumps etc... So it took a few more rides to get it a bit stronger but it's been fine ever since? (I think - I can't remember how much it clicked before I broke it!)

http://snowboards-for-sale.com/red_snowboard_pads/impact_wrist_guards/

those are the ones i use if thats any help.

Thanks very much for your replies, its been informative and very helpful.