If customer wants to use different or alternative ways to connect their, just add inbound entry point in the configured bus. Dot. Mule supports natively: JMS, SOAP, EJB, TCP/IP Socket, RMI, etc. You can write a custom transport component (called Provider) and plugit.
All transformations will be reused. Transport now is a very small detail ;-)
Unfortunately MULE doesn't provide a CORBA transport, so we moved outbound CORBA calls at Transformers level. The clearest solution was to write a CORBA provider (using OpenORB implementation for example), but time was very short.
In conclusion I'm sure to use Mule in future applications, since transport and transformation concept are very common and with Mule the life is easier ;-)