Here's a picture of TFP Shell:
A Starkit is available. This particular Starkit has support for x86 NetBSD and x86 Linux. (x86 is a generic term for i386, i486, Pentium, etc.)
The latest source tarballs can be found in this directory:
Don't use a threaded Tclkit! tclUnixNotify.c has a horrible known bug with fork in threaded builds.
Colin McCormack noted a double-free error on exit in Debian. I haven't been able to duplicate this with ElectricFence during my tests.
There's still more that needs to be done to the tfp.so extension, so that I can support making the router process exit, snd thereby the rest of the children (without Ctrl-c).