There's a guy named Bruce that's rebuilt our OEM shocks.
http://www.brucessuspension.com/
At least 2 owners have had him do it (Little Beast, VR4-QUEST)

Here's some old threads on it, including recharging them with nitrogen.

http://vehicross.info/forums/showthr...ighlight=bruce

http://vehicross.info/forums/showpos...1&postcount=12

http://vehicross.info/forums/showthr...s+shocks+bruce

http://vehicross.info/forums/showthr...ighlight=bruce

http://vehicross.info/forums/showpos...9&postcount=14