Bereft of any decent photos, ain't been outta the backyard for days and days working here and there on Jaunty or sitting inside recovering from the ailment dujour.

Back in the day..when I built organ consoles and bences the company had these from Porter Cable in aluminum to fit one of their motor units but now the Porter Cable folks go, "huh?" when asked about them. These are best made from thicker ply for stiffness though this one is only 1/2" ply. I used MDO ply as I like to use it for stuff regular ply with mebbe formica on the sliding surface would work very well. I have my little trim router sans regular base attached to this.

I adjust mine to 'level' on a flat surface so the router bit cuts at the same level as the slid around base. Levels edges, etc, much as you see to the left in the photo. The nice thing about making your own is you can vary the size and depth of cut potential by varying your materials for construction of it.

I like a knob grip on the end opposite the cutter for easier handling in operation.