+1 for Lochcarron. They make the majority of wool tartan in the world. There's also the VW Golf MK 7 fabric which I went with the 2nd time (below). It's sealed and has a thin foam backing so isn't nearly as sensitive to stretching and staining etc.
I got it at JPM Supply Co but they don't appear to be in business any longer... You can find it at other places now. There are several colors with a dark Grey theme...
