Kiwi Tile (http://www.kiwitile.com/home/) makes high impact polypropylene interlocking tiles that they sell for use in garages, pit areas, shows, etc.
I was considering using them as the finish floor for my woodshop, over a plywood subfloor, laying down some building felt to cushion them. They sell samples and I have tried a 3' x 3' section which seems to work OK; thing with wheels roll, sweeping and mopping is no trouble and they are able to support the weight of the heavier floor tools that I was able to get onto them.
The floor is flat, but over its span rises and falls with the industrial quality floor joists in the unendingly renovated factory building that I call home. They are also appealing since I can handle the individual units (they are 13" x 13" and weigh nothing each, which suits my ancient back!) and will eliminate the need for dash patching and sanding the floor before laying any type of roll goods or epoxy painting.
If anybody has any experience with this type of tile, or has any other suggestions for finishing the floor, I'm all ears.