countryboy,
It seems like your idea would work well, but I wonder if the hitch climber would be off balance when you had the system anchored down low? I didn't really get a chance to hang on the hitch climber when it was attached to a bridge so I can't really say for sure. Let us know what happens, pictures would be cool too!!
Pat,
That CMI pulley certainly looks like it has some good applications. I think it was originally designed for use as an attachment point on a bridge, such as on the Glide. As far as using it with your climbing hitch to advance your knot (like a hitch climber) while also being anchored into to it I find that there isn't much seperation between your lines which often causes your knot to rub up to and hit against your anchor carabiner. The lack of seperation between the lines also can make it more difficult to work your knot. Admittedly I haven't worked off of this system too much in real life situations, but in basic testing I didn't like the effect too much. I know loads of climbers love using this piece to advance their line so you may want to get their input to offset mine.