It is not possible to change these.
To my knowledge, com.process.integratedapp is the master program, and all the various clients are stubs.
Using the Echo SDK would allow you to create an "optimized-mode" application, but it would not show up in the Simultask picker.
The only additional Simultask application that I really want is Document Viewer, because I would like to have better access to documents when responding to an email.