To answer some of your other questions:
Yes, you can daisy chain relays but it usually is unnecessary. (There are some cases to daisy chain relays such as fail-safe protection.)
By good source for relayed 12v, do you mean good place to buy them or good place to get more information on them?
-- If you want more information, try here
** In a nut shell, pins 30 goes to a fused hot (positive) lead, such as your battery's positive terminal through an in-line fuse. Pin 87 goes to your device's positive supply connector. Pin 85 goes to ground. Pin 86 goes to a switched positive, such as the tail light (NOT brake light), day-time-running light, headlight (NOT High Beam), etc.
You can pick up cheap power outlets and relays from your local auto store (AutoZone, O'Reilly's, Advanced, etc and some WallyWorlds) If you have a Fry's Electronics in your area, that is another great place.