I had the same problem and wanted to change the bushings for the hard poly type.
Kevins Offroad sells this type of hard poly bushings. I finally didn't buy it there, because they didn't accept foreign credit cards.
I finally bought a complete new trackbar via Rockauto.com.
If you decide to buy something at Rockauto, i have a discount code valid until January 13th 2013: 120583489869011
JEEP Grand Cherokee 4.7 Lmtd 2004
HID 8000K in low and fog / Quad Squad member
KYB Gas-a-Just shocks / Pirelli Scorpion ATR 245/65/17 - Transgo reprogramming shiftkit.