Ramjet,

I fly off of a rock dust (dg) field quite frequently. There is a great deal of drag on highly loaded wheels (most jets). I don't recomend that way to go.
The East Bay club that flies at Livermore, CA has a rubber mat runway. It works great as long as the seams run the same direction as the runway. Looks like a good way to go and I was told it is much cheaper than asphalt.
I remember during Nam the military had a roll out plastic runway. I don't know if it is still available, but it would take C-130s, so I guess it would work for model jets and such.

Good luck,

rcdoug