one small suggestion might be to try the following:
www.acekaraoke.com/ha2kkm0701.html (Audio2000'S AKM701 digital echo karaoke mixer)... a low power, but versitile piece of equipment. No mixing would be possible, but you could switch players with the push of a button... have your rsq 505 on the VCD and your "decent apex dvd/vcd player" on the cd... with a single button you would change your INPUT selection.
another option might be
www.acekaraoke.com/ha2kkm7015.html (Audio2000'S® AKM7015 key & digital echo karaoke mixer)... which has two mics and two music inputs...
again, mixing would be nill. For home use, my guess is it would be okay.
Matt