I'm 6'1" and wear a 35" inseam in jeans and pants. My legs are long, for sure, but at this length, there are still plenty of options for me to choose from (big smile here!). If you fit into this category, I think you'll be happy with what you can find online.
Alloy Apparel ($) is a good bet for finding 35" inseam jeans. They have a variety of denim styles in this length, from the ever-popular skinny jeans to bootcut and flare. I've bought several Alloy jeans in the past and they are all still holding up nicely. Try Alloy for their inexpensive options and variety, plus free shipping on $100 orders!
Buckle ($$) is a great store for longer length jeans. They have a large collection of mid-priced and designer denim on their website. You can also find Buckle retail locations at malls across the country and they often keep a selection of long lengths in stock in their stores. While Buckle does carry some skinny styles, most of their jeans are of the bootcut fit with stretch.
EXPRESS ($$) is my favorite shop for jeans. Like I mentioned before, I am a 35" inseam, and that is the length of Express' tall size. The way that their denim is cut is the fit that I feel looks best on me out of all the ones I've tried. I know everyone has different body shapes and what works best for one person may not be the same for another, but Express jeans are my definite go-to. Their styles are typically between $50 and $100, so the pricing isn't bad either, especially when you catch them on sale.
Long Tall Sally ($$) doesn't usually have too many 35" inseam lengths available, but because they are such a great tall women's clothing source, it's always a good idea to look over their collection.
Gap ($$) is a very well-known clothing company. And, most ladies of height are already familiar with their tall sizes. What I like about Gap is that they are constantly changing their collection. So, the variety is there. They are also good about staying on top of the current trends. If you visit one of their retail locations, you should be able to find some of their denim in tall lengths, although you'll find more online. Here's a tip...if you buy from Gap's website, you can return to any retail location for free, if needed. Free shipping on orders of $50 or more and free returns is also a nice perk.
New York & Company ($$) offers stylish and modern denim looks. Their talls come in either a 35" or 35.5" inseam and can be found in a wide size range, from 0 to 20. NY&C doesn't have quite as big of a selection as the other companies I mentioned above, but what they do carry are nice choices for any woman needing this length.
Lane Bryant ($$) is a well-known plus size retailer offering many different trendy looks. Their jeans are designed to give a more slimming appearance to the body. Lane Bryant's talls come in a 35 inch inseam and in sizes ranging from women's 14 to 28.
Zappos ($$) carries a small selection of 35" inseam jeans. Be sure to use their free shipping and free return policy to easily try out their clothing!