Ron's idea of linoleum is a good one but only if the temperature remains fairly stable in the shop and it doesn't get cold in there. Else, the linoleum gets brittle, cracks, separates, whatever. In other words, linoleum doesn't like wide temperature swings.
In my storage shed with 3/4" plywood flooring I put a good coat of primer down then followed up with 2 coats of gray porch enamel. If you need some grit then you can add some of that material that they use for garage floor stain. I know Sherwin Williams has something called "Shark's Teeth" that they add to their H&C stain to give the floor a little "tooth".