Have you looked at rock n republic? I think all of their jeans come is 34 inseam? My bf has seven, true religion, and rock n republic. And he likes the rock n republic the best, he said it's comfortable. And they aren't too expensive at nordstrom rack.
My hubby is a beast! Lol. He does a lot of squats and has huge thighs. He is 6 1/2 feet tall and He has a very difficult time. Although not really designer, Lucky Brand works extremely well and is easy. He also does designer jeans, but has to put a ton of effort into them.
This is totally up my alley! I work for a designer that makes primarily denim this is the number one request we get. From what I have found Rock and Republic or True Religion is your best bet. J Brand for men is also becoming popular and I think they have some wider fits. Stick to American brands as the European companies like Diesel tend to fit narrower.
DH can only wear Tue Religion! At 6'3 with massive thighs and a small waist, nothing else would fit him! Still I have to get him 36/34 and have the waist taken in. Otherwise he can't pull the jeans pass his thighs!