scorpio,
it seems you and I have the opposite problems. I'm 5'10" and have a small waist (despite being fairly overweight - I predict a new year diet). I always find that I can get trousers/jeans etc. to fit my chubby thighs, but they gape around the waist.
Not that this helps you at all!
I know that all clothes shops use different standards that they base their clothes on, whcih is why some shops have a more generous cut than others and from memory, I know Levis have a very slim fit. It might be an idea to go and try on a few items in the stores you like and figuring out which fit you best. Some places (like Top Shop, I think) will adjust clothing for free, usually leg length, but it may be worth asking.
I'm sure Trinny and Susannah would have some more constructive suggestions, but alterations would seem the best way forward. Is it something you can do yourself? Or are you about to make friends with your local tailor?!
happy hunting
Jo