Anyone know of an electric, pneumatic, or hydraulic floor jack?

I've got two of those as in post #7.

They work VERY well if used properly.

Lucked into one for $100 while buying something else, then 3 years later found an identical one for $125 right across the street from my shop.

I made slot bumper adapters from gm bumper jacks and bar stock that work very well and don't scratch the plating like the ones that come with the jacks do.

We used those in high school auto shop and I had wanted one ever since.

One benefit is most all of the operation can be done while standing.

They are actually built so they can be used without stands, but it's a little intimidating. Very good design.

Lift one end, put on stands, lift the other and it's easy to get high enough to drop a transmission. Just make sure the first jack stand point can pivot (like using the rounded out portion of jack stands under the axle).