Found: Retül Levül Height Adjustable Wheel Block for Trainers
Retul’s new Levül adjustable height wheel block helps you get your front wheel level with your rear (or set it on bigger incline than what most molded plastic blocks and wheel trays will allow). It’s a far more elegant solution than one-size-fits-all wheel trays or phone books.
At $349 retail, though, it might be worth making good use of those phone books Yellow Pages seems hell bent on delivering despite this new thing called the Internet. Thanks to Gregory for the pic!