Try Stephen Brooks in the UK - great prices (tho there is shipping to consider). I bought a pair a lower rear 1/4 panels for about $90 from him a few years back. Great quality, great support.
He also sells the FORWARD lower rear Q panel (ie in FRONT of rear wheel) as well as the fender top arch too...
Stephen@sbrooks43.orangehome.co.uk
Stu Aull
80GS
Alaska