Hi Paul,
I understand that they don't exist! I would like that too.
The only way I know to achieve this is by a learning remote to create a macro for each DSP.
It's not elegant!
If you are listening to CD and your default was Music. Say you wanted a Trifield button. Then the macro would contain the code for the CD source(which would be Music DSP) followed by up/down codes (to get to Trifield DSP).
This works on my Pronto.

Tahir

TA