I think it is Paddocks Landrover Spares -
www.paddockspares.com/scp/SHOP_BY_BRAND_I-Z/Pro_Comp.htmlThey are a Land Rover specialist but it is always worth a look at the website for things like tyres, Hi-lifts, Optima batteries and recovery gear etc.
They do sell the Procomp range to fit Landrovers but I can't imagine they would refuse to order Jeep bits on their next order/delivery if you knew what you wanted and paid up front or a hefty deposit. I intend to try for some shock absorbers through them when my current ES9000's need changing.
As I come from a Land Rover background I have an account with them dating back more than 10 years and they are good to deal with. Even when I have had warranty issues they have treated me well.