With my self-imposed material choice constraints (wood), I reviewed the existing plastic design for the 'x-end-motor' and 'x-end-idler', and simplified it to two basic parts per end. I did a dimensioned sketch (below) before cutting anything. I haven't figured how best to secure the motor or idler yet but will return to that, but I think the motor will incorporate relatively easily to my design.
The x-axis and all belonging to it, is raised and lower by threaded rods passing through captured nuts in the x-ends. The Prusa design incorporates a spring between the captured nuts (see here) to keep the nuts tensioned on the threaded rod, reducing rattle or back-lash. I'm going to try a long-nut instead of this. There's little or no play in a long-nut, especially if the threads are lightly greased, and with the thread in a vertical direction I don't expect any back-lash problems.
Here's some picts showing my construction of the X-Ends.
The large and small pieces are cut, and carefully glued as per the diagram. I've also drilled two 8mm holes (60mm between centres) in the base before assebly. These will receive the x-axis rods, but I haven't finalised a method to secure them in place.
The nut will be epoxied in. The bushings push nicely into the top and bottom of the 8mm hole to receive the 6mm rod. secured in with a dab of pva.
Here's both X-Ends loosley assembled on either end of a pair of 8mm rods.
What has occurred to me though now having got this far, is that the whole thing might work better 'upside-down'. It would give more free area for mounting the motor/idler and the the long-nut would be pushing the assembly rather than pulling it! (see pict below)