I've used Lowes (Home Improvement store) in the past with good results. We had some expensive carpet leftover from an installation and took it to the Lowes flooring department where they cut it to our custom sizes and put a nice binding around the edges.
You might also check out www.theperfectrug.com
- where you can pick the fabric, border, shape and exact dimensions to the inch.
Also, if you can live with standard sizes, Ruggables work really well in a coach since you can easily remove the rug portion from the backing and throw it in the washing machine.
Here's a video the RV Geeks did on ruggables.