Performance

Yes, using CORBA even inside the application is a good idea if you want
to establish clear interfaces. Such an approach is used in a number of
applications today.

>Are there ways to only use this part of an ORB without too much overhead?

The early CORBA specs had been talking about how CORBA would enable
different object adapters, and suggesting the introduction of "Library
Object Adapters". These would sit on top of the operating system's shared
library mechanism, and CORBA operation invocations would be direct 
procedure calls in the programming language. The IBM SOM and the Fresco
GUI kit are examples for this approach.

These days, people rather use a standard object adapter and hope that
ORB vendors make that efficient in the local case. For example, the 
Gnome desktop uses the POA, but most servants typically run in-process.
The CORBA spec does not specify any performance properties, so when
you select a CORBA product, ask the vendor what they did to make the
local case fast.

Dr. Douglas Schmidt hat ein Papier http://www.cs.wustl.edu/~schmidt/C++-report-col18.ps.gz über Optimierungsmöglichkeiten um die lokale Kummunikation zu beschleunigen.

Hoschka: The Marchalling Problem

Überlegung, wie man das Marshalling beschleunigen kann