Keith:
My wife is a quilter and I've done 7 or 8 auto interiors over time (diamond tuft, tuck and roll, inserts, etc) so I guess I can offer suggestions.
Look in the yellow pages for "Fabrics" or "Upholstery Fabrics " or "auto upholstery fabrics".
I just googled upholstery fabrics in Nashville, tn and got 8 good hits.
Many of those places (but not all) carry vinyl upholstery material in a lot of colors and can also help with people in the area who can sew stuff up for you, although the best place might be a local auto upholstery shop.
Why?
Because they have these industrial-strength sewing machines with stitch lengths up to 3/8" which can look good in a car. For instance, the baseball stitch in my F250 is about 1/4" length and the thread is really beefy - something your ordinary home sewing machine would choke on.
Just remember that you might have to buy a yard length of whatever width material you choose so you might end up with some extra kicking around for other projects. I still have some left from when Kathy made a side window carrier pouch for Lane.
Personally, I wouldn't try sewing up a shift boot by hand, simply because the stitch line would show and it's really hard to keep the line straight when you hand stitch, even with a hand-stitcher like this:
http://www.ebay.com/itm/NIB-SEWING-AWL-hand-stitcher-LEATHER-UPHOLSTERY-BELTS-SHOES-COATS-/360394910760
I have a couple of those and only use them when it's an emergency or when the stitches don't show (or can be hidden within the material).
Good luck!
gn