Never heard of one. I would imagine with low resolution and relative high noise level it wouldn't look all that much better than just letting your TV upscale the picture unless you want to invest in some sort of major external scaling device. Then again, I've never noticed all that much of an improvement with having the DVD upscale the video vs letting my sets do the conversion -- never tried an OPPO, but pretty much ever medium level DVD looks about the same and sometimes worse.
Yup, better off getting a receiver that will do some upscaling for SD video sources, than to go looking for a relic (VCR) with video upscaling capabilities.