I'm UK based (London) and I got my parts from the following,
Joysticks/Trackball/Buttons: From Happs UK, I gave their UK unit a ring, gave them the part numbers (taken from the Happs site), paid by card and they posted them off to me and I got them if a couple of days.
iPAC/OtiPAC: From Ultimarc, ordered online and also deliveried within a few days.
Spinner: From Oscar, ordered online, took a few more days to come as it was coming from the states.
All provided good service and I would be happy to order from them again.