Its an interesting thought.
I`d need 5 sheets (4 1/2) of OSB3, wickes are selling for £22 = £110, floor paint = £20.
If I then laid the pvc mats just where I was standing, I bet I`ve just lost the saving of less matting in the price of the OSB sheet.
I just fancied the pcv matting to stand on but I expect with it being so rigid, it i`d be no different than the OSB.
I must admit, I like the idea of raising the floor a little - will the OSB give some insulation from the cold concrete floor or not really without any true insulation under it (which I haven`t got head height for).