Also, I recently found an old ebay listing for a Quest bass that looks really similar to my guitar:
It's the same shape and looks like the same wood type, and you can't see in the picture but the listing also said it had two output jacks, like mine.
Mine has no visible serial number and the lister for that bass said it didn't have one either. They seemed to be under the impression it was a prototype.
I do know that there's at least one other guitar like mine though - I saw a picture of one years ago on a forum somewhere (it looked like the same model, with that same shape, except the wood was red at the sides), and it was also a Quest with the same logo. I can't find the picture anymore however. I think it was just posted on some forum somewhere, and there wasn't any info about it.
The closest I've seen besides that is some old BC Rich's with a very similar, but not identical shape. I always assumed whoever made mine was taking some stylistic influence BC Rich, if not making a direct copy.