Is there a way to reduce clutter in a serviced-component's method signature
by collapsing a few of them into a UDT and passing the UDT instead from the
client?

The .Net versions being considered are 1.1 and 2.0.

For example, I am thinking of creating an assembly that exposes UDTs. This
assembly will in turn be referenced by two assemblies, one of which contains
the serviced-components and the other contains GUI elements that call methods
on the serviced-components.

Would there be adverse performance implications if this is employed (and is
possible)?

Regards,
Tristan