There is always shunting scrabble (usually played at shows to avoid boredom) Wagons have a letter tacked on the non public visible side. Trains of wagons arrive and the goal is to send back completed words with the highest score. Wagons are also arranged so that common wagons have common letters while Z, Q etc are unusual one offs.
I'm sure that there would need to be a few more rules than this (I've been informed that this is about it). Maybe the scrabble set to draw the letters out for the incoming train.