I have to admit the idea is interesting and my DGS loves Legos but, I drive a Class A with dual rear wheels and in some cases I need to raise an entire side 4.5". To be safe and provide a 9"X9" top level(I would prefer the 9"X18" top level), would take 45 blocks(49 for the 9"X18" top). That would cost over $150.00 and would take up as much room as my three ramps of 2"X8"s three levels high. My three ramps may be much heavier but, the fast and easy to just lay on the ground at the tires, no assembly required, no bags to store and just as easy to disassemble and store when we're ready to break camp and move on.
Maybe if I had a TT with one axel but not with an A. I am hoping my next rig will have hydraulic levelers which are even heavier than my wooden ones.