Just a small shout out to the SuperMagnet Man: http://www.supermagnetman.net/
I ordered some 100 small (1.5mm in diameter, 0.8mm tall) aboubt a week ago and I must say they were impressively strong. It's also really is a nice site with decent prices. The shipping was prompt and he sent out e-mail updates at each stage (Processing, Packing, Shipped). My only minor complaint is a lack of tracking service, but my order went from Alabama to Maryland in 2 days (Ordered to in my hands).
It's probably also worth noting: Those magnets were the perfect size for fitting in the various slots on the Crisis Suit and the back slot on the Stealth Suit. They also happened to match a drill bit on my pin vice perfectly, which made it all just ever so simple.
1 magnet in the suit and 1 in the weapon is more than enough for 80% of the people out there in terms of hold, but I think it was worth the effort to do 2 side-by-side, it makes them a lot harder to knock off and they don't rotate so easily. This does make it a little more important to line them up right on the weapons (the XV8s have straight slots, so you don't have to worry about the suit so much.)