LightngSVT- Dunno how long this link will work either, but Griot's calls them
Movable Car Jacks . The PN is 77730 or 77731 for the heavy duty ones.
I use them for exactly what you're considering and I can get cars into the far corner of my shop where it's such a tight fit that people
about how I did it.
But as I posted earlier, it takes a little effort and experience helps. The first few times I used them I was pretty disappointed but I'm glad I stuck with it as I really like having them now.