Hello.

How about a place for all of the radio mods?
A classic example is the VX-3R.
This thing has 3 levels of mods.
The first being the MARS/CAP mod, remove the jumper and reset or firmware settings.
The second level is primarily firmware and is the "Freeband" mod.
The third level "Owned", where the firmware now has a bit-bang interface and can transmit pretty much everywhere it can hear, and this comes in 2 flavors, the first being no physical mods, it is all done in firmware, and hardware hacker.

But, be this as it may, there is a lot of information out there.
If you have never programmed an older Motorola radio with a RIB, and understand how easy it is to "brick" a radio, do not do level 3, you will be sorry!
Everything must be just so, as once the transfer begins the radio no longer has valid code, it must compile from the new code or it is invalid.
One of the reasons that a RIB has a battery backup, and an AC adaptor, and the bench supply, and the laptop power,,,,,,,,,.
http://www.batlabs.com/2wayrib.html
And, to answer the question, the VX-3R will do from 56 to 556MHz transmit with no gaps but the ones where the tuned circuits fall out, adjustable in softpots.