I am planning to build a 4'x3' usable area router. I want ball bearing linear rails. Rectangular rails look better to me, but there are fairly cheap sources for 20mm round supported rail and carriage (eg VXB). Is there a reasonably priced source for rectangular rails? Are the VXB round rails any good?
You might try Rockford Ball Screw. They also sell Linear way systems. I have recently been quoted for 15mm size rails and bearing blocks. Very reasonably priced.
My cohort in crime and I visited their shop and found a substantial stock of rails etc. in stock. Since they are within driving distance from us, no lead time.
Works for me.