FT5 Double X Slide Carriage

I've had a stock Folgertech FT5 R1 for about a year now and have hundreds of hours of good successful prints with it. Many have modified theirs and that's part of the fun of printing, modifying and improving the machine. Of course many mods have perceived improvements of print quality, many are just wish-list, and some are actual worthwhile improvements.
The only thing that has bugged me about the physical part of the machine is the single linear rail on the X axis, the rail that supports the