Motorola radio can't do *everything*
My opinion is don't buy that crap. Dont drop 600 or 700 bucks on a radio to where their company GRE is out of business with no good support anymore. Can't get a hold of the company by phone or anything.
If you need to receive Phase II or X2-TDMA just wait until a company comes out with the latest and greatest radio if they ever do. Dont get taken advantage from online or ebay buying these cheaply made radios.
Another option is put your money into a commerical grade radio from Motorola. Its big money but worth it in the long run.
The main reason enthusiasts don't buy a dedicated /\/\otorola transceiver for receive-only purposes is because they want a single unit that will do everything with more mainstream programming ability. Besides, much of the time people are scanning multiple trunking types, some of which an actual Motorola radio CAN'T do. It would require carrying around not only your regular scanner but a second radio as well.
While I completely agree there's nothing finer than a Motorola radio, it just doesn't make sense for most scanning enthusiasts to do what you suggested unless they just listen to a Motorola-only system. Then perhaps it's a good choice IF the person doesn't mind acquiring the necessary RSS/CPS and programming hardware, and of course learning to use it. If a person were to fit this scenario then I agree you wouldn't find a better method to monitor it.