I am guessing homemade. Nice design though, better than alot of crap I see on c-list that are thrown together, not painted, no jack heavy on one end, and asking new price for them claiming "heavy duty"
Couple of reasons I think it is homemade...
1. Pump coupling is exposed and no gaurds
2. "Most" factory built logsplitters dont use tie-rod cylinders
3. most use a more substantial connection between pusher and beam, and alot of times greasable
4. Most have something on the pusher to keep logs from slipping, pieces of metal, washers, etc.
5. No markings at all.
Dont have any info on the motor.
Tonnage would be based on cylinder diameter and pump pressure. Looks like a 4" cylinder which would be "rated" by the big MFG's as somewhere between 18-22 tons.
Judging from the speed, it looks like an 11gpm pump. Which is typically paired with at least a 5HP motor.
And yea, any hydraulic oil will work.