It sounds like you need the man who taught Barry White everything he knows... knew?
That's right, Jim Gillette.
@Bart Ell I have those tapes. As funny as it all is, they really work. I still use a few of my favorites as my general vocal workout to keep things nicely oiled.
"Now let's do the,
Ee Ee Ee's going up!"
"
ZEE A O I A AH LAY MINE" repeat by half steps up and down.
"
YAa AHH" from octave to octave and so on repeating up and down.
..and many many more