There is the lowrider S-10 by revell, could be a good donor chassis.
also they did the lowrider thing to the elcamino model. both are more pricee than thier stock counter parts, but here in Mn we have micheals crafts , and they run 40 to 50 % off coupons most weeks so it helps take a bite out of te cost. toy liquidator, a K&B toy outlet also had the S-10 for around $6.00.