I have a front projector (think sales presentation) which has NO conversion capability. It accepts RCA, S-video, RGB and VGA. I have 2 VCR's, 1 DVD, and regular cable.

I use one of the VCR's to convert the basic cable (Time Warner, if it makes any difference) into RCA. All of the devices are switched by an amplifier, which in turns sends either RCA or S-Video to the projector (That's the only input types that I used - 2VCR + 1DVD). The projector is smart and determines which feed to use (S or RCA) depending on which feed has a signal.

This has worked very well for me.

In the OP's case, his TV could easily do the Cable conversion, while other inputs on the TV would allow VCR/Video/etc. Alternatively, an amplifier would allow the switching..

HTSC