my laughable idea to upgrade radio

Hi: I asked my Toyota dealer's parts department guru about upgrading the standard single CD radio to the deeeeeluxe radio / 6 CD changer. I correctly guessed that it would involve more than just swapping out one unit and shoving another one in. There's the interface with the computer and the MFD, etc.
Well, we never got that far in the discussion, i.e., how to interface with the MFD. I was stunned to find out that the deluxe radio and changer costs nearly $1200 bucks. Factor in whatever it would cost to connect it all to the MFD, if it's even possible to do that, and we are talking "airplane parts levels" of monetary outflow.
The dealer guy said it might be simpler to go to Car Toys or someplace like that and have them install a CD changer that would work like a small radio and transmit the signal to the existing radio which would be tuned to some unused FM frequency. Sounds Rube Goldberg-ish, but I think this is how the XM add on radio works.
Have any of you upgraded? If so, how? And what did it cost you?
Bob
p.s. I wonder if there will be an aftermarket for fake autodimming rearview mirrors and dummy steering wheel buttons, to make our medium tricked out Prii (options 1-7) look like the maxi tricked out number 9's. (that would be option 4 looking like option 6 for you 2005-ers)

 

Is the changer separate from the radio? I thought it was all one unit. Does the changer fit into the empty space under the radio in the standard radio option packages?
How would that changer interface with the MFD?