I'm not sure what Chinese quad brands have the gy6 motors. I just know there are a bunch using basically the standard street scooter driveline with the added chain drive box. They just hang the whole scooter driveline off whatever mounts the quad wants. The engine is the same but drives a chain to the rear axle rather than the usual rear wheel.
I'd guess anything in the 150cc area is a good candidate to search for, then just look. The scooter motor quads are easy to spot from the fan shroud shape. They come in 50cc to 150cc or so under dozens of names.
Here's the chain drive box:
If more is better, then too much is just enough.
If you can't afford it, build it yourself.