Cycling Trousers - The Long and the Short of It!

Buying a new pair of cycling trousers should be a simple enough task but recent attempts have left me at a loss to understand what some of the major cycle apparel manufacturers are thinking of!  I'm after a pair of long waterproof overtrousers so headed off to my LBS to find out what's available.  The first thing that astounded me was the price range, starting at £40 for a basic pair of Endura Nevis to an inconceivable £160 for a pair made by Gore.  I tried on the Nevis pair in my waist size to fine that while the waist was fine. the legs were a couple of inches too short.  I then tried a pair of Altura Attacks, this time the leg length was fine but the waist was massive, I tried the next size down and couldn't even fasten them up!  Going back to the first pair I adjusted the velcro tabs on the waist and found that I could just about get them to stay up properly. £106 poorer I left the shop already questioning the wisdom of my decision.  Later at home I inspected the trews more closely it transpired that they were incorrectly labelled and I had in fact bought a pair of XXL, big enough for a hefty 41" waistline.  I then took a look at the sizing guide on the Altura website and was astounded to find that, according to Altura, length is directly proportional to waist size and that XXL is my only option if I want a pair of trousers to fit in the leg.  I accept that  may be taller than average but I have no trouble buying normal trousers from any high street store.
Endura don't even disclose the relative length of their trousers and I have a strong feeling that they also adopt the same taller = wider approach.  It seems to me that cyclists are being taken for a ride with overpriced clothing with only a slim chance of a good fit!  Is it because they think we mostly wear shorts?