Is there currently a way to put multiple VST instruments on a single track so that when I play the keyboard it triggers more than one soft synth?  I know I could set up separate instrument tracks with the same MIDI input channel and set them to input echo to accomplish this as well but sometimes I'd like to just have one track with layered VST instruments.

I do it sometimes with multiple instruments loaded into a single instance of Kontakt, where I then set each midi channel to 1, and adjust volumes within Kontakt to get the desired levels.
 
Bob Bone
 

I guess you could do that too with the TTS-1 synth.
 
Bob Bone