In reply to Mr Fuller:
Another vote for berghaus. The cyclops back system is great with heavy loads.
I used my Vulcan on the Pennine way and carried way too much stuff (mainly food and water) and tipped the scales at 25 kilos and it felt fine. It's carried heavier too when folk in green gear made me carry other things too.
I've got a newer civi style cyclops which is really good with weight but it's not carried anywhere near 25kg!
I would be very tempted to try an Aguille Alpine pack on first if I was buying now though.