Okay, I don't know of any bike shop anywhere that you can walk in and count on finding a touring bike in your size to rent or buy. I'm sure there are a few, but they are very few indeed and none are known to me. So if you want a touring bike, you'll need to prearrange. I know some good bike shops, but I don't know of any with much touring knowledge. I can highly recommend Wheat Ridge Cyclery (in Wheat Ridge) and University Bikes (in Boulder). If you need a touring bike on the spot and did not prearrange, then your best bet is REI. The flagship store is in Denver. They typically have one or two LHT on the floor, but it'd be pure luck if one was in your size.
You can usually count on REI to have some Ortlieb and Novara panniers and Tubus racks in stock, especially at the Denver flagship store. That store is probably your best chance at one-stop shopping for a bike and equipment. Shop around at their online web site and submit an order for everything you need. Have it delivered to the store and it will be ready for you when you get there. REI typically carries three kinds of touring bikes (Novara Randonee and Safari, and the Surly LHT)--you'll have to figure out the size yourself. I do not, however, currently see the LHT in their catalog.
If you order a bike through Wheat Ridge Cyclery or University Bikes, you'll likely get much better service making it fit you. These shops can readily swap out stems and saddles. They can probably order many of the bikes in the ACA buyers' guide.
Note that if you walk into any bike shop and ask to see their touring bikes, they will most likely not have any, but they will try to convince you that some bike on their floor is "practically the same thing." So if you want a real touring bike, and I do recommend you get one if you will be doing much touring, arrange ahead of time for them to order one.
I don't know of any place that rents touring bikes or touring equipment.
