So i've ordered the printed components from shapeways (SLS nylon) but the lead time is quite long, so will see how quick those parts come through.
The linear variable resistors (ALPS RS08U11AZ001) have arrived - really small, see below;
And i've ordered the boards that these mount to from OSH park. Kicad render below;
This has been designed for both the LB1935FA and LB1848MC bipolar motor control ICs, as i've still got a few pieces of the now obselete LB1935FA. There is a single pin difference, so its a case of cutting one of the tracks, depending on which one is being used.