These guys at Wondermat sell mat tiles at $1.62 per square foot. Still a little pricey? The idea is that you take each square and make track tiles as described above. Some corners, some curves, some straight. Then you assemble a modular track!
I am thinking, you could take a few tiles and cut them into strips, then glue the strips on as flexible barriers. The idea is that the barrier is made of the same foam as the roadbed. You enter with a handful of foam tiles and in a few minutes, you throw together a track, fit for any house, through doorways, around furniture, etc. The real work is constructing the tiles, and choosing what shapes to use over others. There is that PC program out there, Trackmaker. Excellent tiles in that.
I realize this is basically what you just said, but it's such a great idea! Someone should run with this as a business plan. Make the tiles, a little smaller than the flooring industry kind, and mold the barriers right into them. Make a whole set of these with different shapes.
Everyone could get in on this. Someone should start this and setup the template for making the linkages match. In other words, develop the system so anyone can make their own tiles and they will interchange with everyone elses!
www.wondermat.com