This is a (you guessed it!) "Goldilocks" just-right solution to my needs, cobbling together some already brilliant designs that were out there. I wanted to reroute the bed wiring without drilling, stabilize the X gantry, and I wanted to be able to generate the parts on my own little 3D printing pal.
The foundation of the whole shebang is FDM_Guru's X Gantry Support System, and while being an excellent solution, will not print on the smaller MPSM in one piece. The first thing I did was slice that sucker in half and add in dovetails to join the seam. A fan/guard would act as a seam brace as well. I've included a 40mm fan guard in a lovely honeycomb pattern on the off chance you don't already have something in mind.
I liked the cable duct on jctots's Side Cooling Vent Remix for No Drill Bed Rewiring, so I surgically extracted it and mixed it into the newly split panel.
I found that the jigsawed together panels needed a little support, as there was still some mobility in the center of the panel because there was no mechanical fastening to the printer frame there, and that would throw off the angle of the linear rail. Problem is, there is nothing to fasten to. So after some head scratching (and head bashing on my desk, you know, for inspiration!) I modeled a little brace that would snap in from behind the standoffs below the mainboard and let you get a screw into it through the side panel.
Lastly, I had to remake the gantry bearing mount as the screws did not line up the same as FDM_Guru's did on my printer. I have a v2, and possibly a later model one at that, so it stands to reason the screw locations may have varied. To be honest, it seems that is a common issue, and I wouldn't be surprised if mine wasn't a perfect fit for yours either. All I can say is, it works for me and may be a good starting point for you. Consider it a rite of passage to tweak the bearing mount to suit your needs.
Oh, and I swiped the 6mm linear rail cap from mdkendall's bearing holder design (see! he had to make on for himself too!), because let's face it, that's a genius finishing touch.
One final note: I am going to abandon you to your own devices to plumb the source designs for all the various bits and pieces to purchase and pull all this together - linear rails, bearings, etc. Again, it's a rite of passage, and the exercise will do you some good.
PS: this was one among my earlier works (and done in Sketchup, which in hindsight was likely the long way around the barn, but live and learn), so it may be a little rough around the edges here and there. I post this not to be perfection, but possibly to be useful to someone who is heading down the same path as I was, and I can save them some effort.