Found that one in ryde but to us it seemed like you can't go there and do what us as skiers would wanna do. Like you have to be part of the club or something and do their courses because of insurance and stuff.
Its still worth calling up and making some inquiries though...
Monster Skate Park at Sydney Olympic Park has a good Tramp but thats all that i know about!
I go BMXing there every so often on a sunday night and tramp when i have a break.
There is also a foam pit right next to the tramp if you wanna try huck something!
Pretty fun !!!