Hi Korhan

> modules and I'd like to keep it that way. However, I am open to suggestions.
> For example, I think I should go for a joystick module. The A-164-1 is also
> a nice one, but with this setup, I do not see anything controllable by gate
> signals (my eyes are not really trained to see these things by the way).

The S&H/T&H needs some kind of trigger/gate. You may get it from the
LFOS, but doing it manually is much closer to the real musical development.
Also the VC-Slewlimiter, can use it (switch portamento on/off).
The VCA can use a gate as organ like envelope.
The gate through the slew limiter is a Attack/Release Envelope.

> Summary: I seek a system that consists of a minimum number of modules
> possible to allow me to design 3-4 processes and have access to them
> simultaneously with no or little patching on stage.

I do live improvisation sound (originating from the A100) and live
processing (originating from something else and beeing processed in the
A100).
What you definitely need for processing external signals is a crossfader
function. Without that you cannot enable/disable the processing without
noticable breaks.
You do not have to use a crossfader module necessarily. You also may use
several multiples and a mixer at the output (either an A-100 mix modul
or an external mixer).
I built some very simple crossfaders for my own. But meanwhile I prefer
especially to have multiple outputs on each soundprocessing module. So
you can setup a second connection to another module (or mixer channel).
The final crossfading usually can be done by the input controls of the
corresponding module or mixer channel.

Florian