A bunch of car rims will fit, but the offset isn't the same. 4x114.3 is the car pattern. Cat wheels are 4x115, so .7 of a millimeter difference. You could go with 14" wheels and mount car tires on. If you want something a little aggresive, last time I checked general grabber tires were available in 14". That's a All terrain truck tire.
If it was me, I think I would put on a set of wheels and ITP's bajacross or ultracross tires (15") and forget the car tire idea.