I've got a Rockshox and its great until you try to find spares (o-rings/washers). even though it can be completely dismantled, you can't get the spares ! (my LBS also tried Madison, and got nowhere)
Just got the DNM as mentioned above as no joy on the Rockshox spares. Firstly the adaptor supplied does not fit my SID rear shock so the leak-proof valve idea does not work; but I have the original one supplied with the Rockshox. (has anyone tried to make sense of the translated instructions on the box !?). Pump is very solid looking, (looks better built than the Rockshox), but seems to be able to only get small amounts of air in the shock on each stroke; the Rockshox gets about 30 psi each time. Good price on the DNM from Chain Reaction (good on most other things as well) so spending £25 as opposed to £50 for something that you won't use that frequently (once you get the correct pressure sorted out for your rig/style, and your shock doesn't leak) is the best bet.
I'm still looking for Rockshock pump spares; anyone got any ideas as distributers (via LBS) said they do not do them ?
For spares try a hydraulics servicing place. Try yellow pages. Or if it is just O rings that you are after, just visit your local Vauxhall/VW/Ford/ whatever Main Dealer spares dept. But not on a Saturday morning.
Oh, and take the pump with you, so they can see it.