I recently discovered Interior Fabrics in Highlands Ranch. It's on the corner of University and County Line. They have a wonderful selection of decorator fabrics for drapery, upholstery and bedding. There prices are fabulous - silk dupioni for $12.99/yd. The staff is very helpful and nice. The only disappointing thing is that it's a small store and they don't carry any of the extras - like matching thread, hardware, etc.
It's mostly interior designers/decorators that frequent the store and so the staff seems to get to know everyone. But it's not intimidating at all as a "regular" joe.