I have a 36" inseam as well (but I'm a size 10). In order to wear heels, I need an inseam more like 38". I've never found a better pair of jeans than Citizens of Humanity. I buy them at Nordstrom. Yeah, they're pricey, but they fit and last forever. I have a few pairs of Seven for all Mankind jeans, but I don't love them, as they tend to be a lower rise jean, and I hate showing butt crack when I sit down! LOL
Otherwise, you can order online via Old Navy, Gap, and Banana Republic (all the same company). They have 2 different sizes of lengths - tall and long - one is 34" and the other is 36" I believe. The other thing I was going to suggest was longtallsally.com. It's a website full of tall sizes for women! They have not only jeans, but long-sleeved shirts and jackets for us tall ladies! Since you are a smaller size, you may also check out Ann Taylor and Ann Taylor Loft online. They carry long inseams, but I find that their clothing is cut better for smaller sizes, so their stuff doesn't work all that well for me personally. But being a size 4, it may work well for you. Good luck!