If by touring, you mean self supported, camping expeditions, then these will do the job:
The cheapest decent touring bike would be from REI.
Next up is Trek 520, but you need to change the gearing down on that one.
The Bruce Gorden BLT is a highly respected model, from a touring specialist, built to compete with the Trek on price.
If you are more into hostel touring with lighter loads, then a lighter wight bike will do, such as http://www.jamisbikes.com/bikes/aurora02.html
Above this price, you are looking at buying a stock frame (sometimes with optional brazed-on fittings) from a framebuilder, and getting your local lightweight bike shop to assemble some sound components.
If stock frame geometries dont agree with you, then a custom geometry frame, made just for you is the ultimate touring bike.