Saddlebags come as a set (2) with steel tubular mounting frames that bolt directly to the seat subframe. For pricing, you should send an email to Adrian at: astewart@brammo.com. Maybe he'll chime in here though, eh... "specialone"?
As far as security goes, you should know that your bike has an immobilizer system which uses a RFID chip in the key to "unlock" the system. If the thief doesn't have that key, there's not much hope they're getting the bike started. It'd also be pretty hard for them to "part out" the bike as there aren't that many applications for 6 Valence lithium ion batteries out there.
If you're looking for something more, I would recommend a disc brake lock, although they are pretty dangerous in the event that you forget to remove it prior to trying to ride (think major expensive damage).
Hope that helps...
