I highly doubt there's somewhere they won't put your car on a treadmill for the emmissions test. I got collector's plates here in Ohio, all I have to proove is that it's not my sole means of transportation, and I'm "E-Check" exempt!
Now, OBDII cars only need to pass a scan on the ECM, it's scary how close we're becoming to Comifornia here in Ohio. I'm pretty sure that now OBDII cars don't have to run treadmill test.
BTW: The last time I got my Saturn "E-Check"ed, there was some lowered Jap-crap out behind the station, parked in the lot. But at our station, you pull onto the rollers, and then they lift up to contact the tires... so that ricer must have been VERY close to the rollers to not clear his body kit.