This sounds like a rather trivial feature for an aspiring userland developer to tackle. One could even be "fancy" and bind into the Hijack menu system from userland for the "enable/disable/interval" settings.

Now, while I could have stuck it into Hijack in about the same time it's taking to write this message, there are now growing numbers of complaints that the Hijack menu is becoming "too large" (not sure I understand how it can be "too large", though -- spinning the knob is very fast, and the menu "remembers" it's current location for car/home use).

..