I've made a set for my Morris Minor. Just using regular wool blend house carpet. The most important thing I found was to get the "grain" right.
Before you buy any, flex it to see if the base weave is more exposed in one direction or the other. Then cut your pieces so that the base weave is not seen when you lay it over bends etc. If you are taking your existing carpet out, use it as a template, or take your seats out and take measurements.
Many carpet places will sell off cuts or end-of-rolls at greatly reduced prices. This wool blend stuff was $25 for about 3 roll metres. I did the edging myself because I wanted it to look original, but there are mat places that will do overlocking on the edges. I was quoted $6/m at one place.
In the end it took heaps of work, but I'm really happy with the results.
