Pioneer made quite a few RGB capable laserdisc players, most weren't available in the retail channels though, they were sold to Broadcasters and put in Kiosks and Lasedisc arcade systems. There are plenty of them out there. We even have a laserdisc burner that we used to use for frame by frame computer output in the 90s before digital recorders became the norm.
You can still find RGB players on ebay, usually they have come out of information kiosks, or virtual tour rides etc.