My guess would be to put Linacoustic or Pink Fluffy on all hard surfaces behind the screen. You might lose some performance using ship lap, but I bet it does wonders for the WAF. I'll just have to make sure my wife doesn't see this thread!
7.1.4 Theater Room (In Progress): JVC-RS46U, Silver Ticket AT 2.35:1 142”, Onkyo RZ830, Anthem PVA-7, Panasonic DBT-110, JBL Studio 270’s, 4 - 15" DIY Sealed Subs
3.1 Living Room: Samsung 64” F8500 Plasma, Anthem MRX 300, Dynaudio Audience 52’s, Dynaudio Audience 122C, NHT SubOne