This upgrade uses the 10in rods that are initially used for the z axis and re-purposes them for the x axis while using the metal bed from the makers kit. Since there are bolts protruding out of the bed and the inductive sensor placement, the usable area is only upgraded to 150mm in the x axis, but that's still an improvement without buying an expensive piece of metal! Parts that it requires are listed below:

10x 16mm M3 Bolt
5x 20mm M3 Bolt
2x M3 Nuts
1ft GT2 Timing Belt
4 Zipties
4 Springs from Clicky Pens

4 of the 20mm M3 bolts are used for bed leveling in conjunction with the springs from the clicky pen. The final 20mm M3 bolt is used to trigger the X end stop. The rest is pretty self explanatory when looking at the pictures.