Try to get the builder to pay for all the built ins (in wall speakers, keypads, vol controls, etc.), offer a standard package of wiring to the builder for a good price, then put together upgrake packages (surround, one room audio, etc.) and meet with each buyer before the house is built. You should make plenty of money this way. Also, check the builders payment terms, a lot of them can be notoriously slow. One last thing, if you're not doing security, do it. Either do the monitoring yourself or wire for it and sell the account to a big security company. That alone could make the project worthwhile.