Huck, if the table will hold liquid, take the linoleum off and scurb down the surface witha stiff steel brush, Vaccum it off. Then get some of the grey putty that the floor guys use and float out the surface. You could even use cement. just lay a couple level screed boards to get it level. once it is levled out, then you can put you mdf down on top. You will have seams though. This would be a lot of trouble and expense, and I think the idea of a new table, one you could take down and move later if needed would be money better spent. I would build a 4x8 table top, 2 sheets of 3/4 ply laminated together and set on six 4x4 legs framed together with 2x4's Use 1/4" lag bolts and counter bore the holes so the heads are below wood surface. For $100, you could have a killer work table and like I said, a few screws and it is a kit waiting for a new home.

Man, I wish I had your problem.

Don