The cylinder on my press came from Surplus Center....Here is a link to the 6" cylinders they currently have...
https://www.surpluscenter.com/sort.a...c&keyword=HCD6
I appears they have strokes from 8" up to 60" in stock....the 8" stroke is selling for $569.95.
Big bore cylinders are not cheap! Once you get past 5" bores, the price goes way up.
This is why I mentioned previously that when you start looking at the actual prices of components, those "ready made" presses don't look so bad.