not so much as a "slide out floor" but im planning on laying a tarp down on the floor large enough to go up on the sides of the walls and attached with nails so the eyelets can side on and off...Once the flooring get ready for cleaning just pull the tarp off the nails and slide it out the main door. Hose off the tarp to sun dry and then put it back in.
Why don't you try those flat pans that they sell in the auto parts stores to put under cars that leak oil? Two of the large ones would do the trick. When they get real nasty, just pull them out and hose them off.