I would second InstallerCarl's suggestion of UPB. The range your are talking about is no problem for UPB. X10 would be cheaper but It wouldn't be as solid as UPB. Insteon in this application would be not much better then x10.
I did an install with a guest house about 200 ft from the main house and had no problems with controlling lighting in the guest house from the main house...
I suggest you give Automated Outlet in Texas a call for your UPB products. They have excellent customer service and right now have a sale on UPB products.
Here is a link:
[Link: automatedoutlet.com]Dave