Is there a way a 8' rail can be cut into two 4' rails? Mainly because 4' would be PERFECT for LPR and some MPR, then when you wanted extra stability, you'd use some sort of metal rod in the center hole, or brackets on the outside, to make it back into a 8' rail. You could also transport it in two sections! I imagine this would take a lot of ACCURATE drilling/tapping, but I think it would be worth it!
Jason