Rick,

You asked for "slidable" chords, so I tho't I'd jump in with one of my favorites — the D. Slide it up to the 7th fret and you've got G, up to the 9th and you've got A. You can vary things nicely with the "long" A (barring the first four strings and getting the 5th fret A note) or A7 (bar 1-4S, G note on the 1S) configurations. Sliding the long A up to the 7F and 10F gives you a D and dropping the 10F note down to the 8F gives you a D7. I don't do it, but you could throw your moveable B7 to the 9&10F for another G form. Lots of picking potential up there.

david