Yep I know the problem. As you say there aren't many options for us long legged types. I am 34 waist 36 leg in jeans. Funny how there is no problem getting jeans this size, but difficult to get outdoor style/climbing trousers this size.
Have you looked at the Kuhl website? I have bought a pair of Revolver Rogues and they are an excellent fit. They are clearly designed for someone with a lean frame, ie not too baggy. I ordered them direct from the USA (no other option on the website) which makes them expensive with tax, and returns could be problematic, but worth a try for you perhaps? I suppose you could try asking a stockist in the UK to order them for you as I couldn't find anywhere that had my size in stock. I suspect it will be easier to buy online though, asking shop assistants to do something slightly unusual for you never seems to go well. One other thing - something told me to go for the 32 waist as they are made of stretch material and they are fine.
A cheaper option is Craghoppers who do a 35 leg version of their classic kiwi trousers which aren't bad. I can just about get away with this length. However these seem to be only available in navy blue so you will look a bit like a plumber or factory worker rather than a suave and elegant climber and they are more baggy than the Kuhl trousers which in my opinion are much more stylish.
I don't know why more manufacturers don't supply unfinished hems......
Hope this helps. Cheers.