David,
Talking about the "single piece of software that makes all the features of the rig available", have you checked out Hamlib recently?  
It's an open source library designed at controling rigs (and antenna rotators), offering an "hardware abstraction layer" to applications.
It's developed under Linux with builds on other systems. Currently, we're seeking GUI developers
and people to help the port to win32.

Site is at http://hamlib.org

73 de Stephane

Good news everyone! The TH-F7E (and TH-F6A) are supported by Hamlib, a radio control library for Linux systems (and others).
Hamlib is an open source project, and we'd be happy to count you in the developer team. Testers and contributors are also welcome.

The web site is at http://hamlib.org

For more information, join the hamlib-developer mailing list at http://lists.sourceforge.net/lists/listinfo/hamlib-developer