Summary of Install:
I have a four antenna setup (antenna farm) in my attic. Two SBGH for UHF, and two Loop antenna for VHF. Each SBGH is paired with a VHF-Loop. Each pair is connected to a Channel Master 7777 preamp.
The outputs of each preamp flows down ~60' of coax to their respective power-inserters. The output of the inserters are combined through a Holland's splitter/combiner and directly coupled to the input of a Channel Master 3414 distribution amp.
Two of the distro-amps outputs go direct to a bedroom TV and my HTPC. The other two outputs are each split with Holland's splitters to another 3 TV's and my MediaPVR.
Best is to view my OTA page, along with diagram and channel reception here
To others that want to install in the attic...it's not easy to find a hot-spot, but when/IF you do, then you're good, and can almost get just a good reception as anyone else. My advice is NOT have more than one layer of roofing shingles. You loose a lot of signal when going through the roof. Additional layer of shingles will not help in the least.
Make sure there are no other metal (duct work, etc) in the attic that can act as interference to your signal. Your fighting against building materials that can easily block signals...you need every bit of open space you can get.
I feel I'm living testament that an attic install can be very successful, rewarding experience.
Best of luck to others that are attempting it.