The BMW club have a monthly journal which often has a 80GS or 100GS in.
You could become a member as it's handy for spares and meeting other BMW riders, etc.
Or you could cheat and just ask someone else who is a member to have a look for you and email the details.
I'm having problems with my membership, so haven't got the March journal yet - but email me if you want me to have a look for you when it arrives...
PDs are a bit rarer, but you can modify a GS to get it near PD spec - this is what I did... and made mine a single seater with rack, 43 L tank, Tesch panniers, Ohlins shock, Wirth progressive spings, bar risers, lower pegs, sheepskin seat, heated grips, etc, etc
Then there's the old paralever, monolever debate... have a look at http://www.ukgser.com
- they have an airhead section which is full of stuff about boxers...
Hope this helps
(I'm quackers about bikes)
(I\'m quackers about bikes)