Voodoo had that setup, using an electric car jack. Not sure if it's the one you were thinking of but same principle:

There's also Uberclocker in the US, and the original Storm, although that used two rams.

Also where would you get a suitable pump?
Andrew Kenworthy (Kenny) was selling some hydraulic pump/motor units a few months ago. 500W ones, good for 140bar, although you presumably couple a more powerful motor to it. The Big Nipper boys strapped a brushless motor on theirs for their featherweight crusher this year. Not sure if he's got any left, but fourth post down here: http://www.fightingrobots.co.uk/thre...parts-for-sale

EDIT: Been beaten to it on both counts!