As for batteries, you might call a local golf course and find out who handled their cart maintenance. Then give them a call and see if you can buy batteries from them. They probably get a terrefic deal on bulk batteries and might pass the savings on to you..
Hopefully you are not going to try and run the whole house on the inverter? When i installed mine i found it easier and cheaper to simply wire a couple of dedicated outlets near the TV's. then using a surge strip it is a simple matter to plug into the correct power.
Personally i think you need to sit down, make a list of everything you want/need to do to make a system you want. Then start putting things in a list in order of priority. And start building your ideal system.
