Larger Camper Stands?

The ones I had were also stackable. I have looked everywhere for pictures. I should have kept them!!!

Sailboat stands.

They have a top that can rotate, but it can be welded at whatever angle you want, and they are really heavy duty.

Google up these....Super Steel Sawhorse Brackets.

I just googled for screw jack stands and came up with a lot of possibilities for larger jack stands. They're not EXACTLY what you're looking for but with a little creativity I'm sure you could adapt and overcome.

similar. The top were half that, like a L shaped. I will look for some pictures.

Because of the description, extended height with cradle to accept 4x4, sounds like a slide out or trailer support? Ive not seen any with larger bases though. These are steel. couple of Amz links just for reference.
Barker slideout stand
husky slideout supports.

While the Camco stands are functional, bit on the small side.
I had picked up a set but ended up using 40+ years Reese set, a lot more robust, taller, larger base-still screw top.

Got pictures of previous set?

Other than Harbor Freight, look at car racing vendors: Joes Racing Products, Griots Garage, JEGS.