Just go the glove box route. Easy to make a template and then let a plastics shop cut out a faceplate to fit in there. They may have an idea for a exterior cover, but it will look odd on the left fairing upper no matter what.
My experiences with radios on bikes has been dismal though, even with an expensive Kenwood I put into my RT when I threw the old BMW radio/cassette player in the trash with all the BMW harness/switches and the squeaky BMW speakers too. FM range is sketchy out of town and lots of static too even on AM. The CD side of the Kenwood was prone to skipping on bumps though and enough bumps would overrun the buffer. Satellite on the GT was better for touring, but the compression and audio quality was sort of yucky with decent phones. BMW has to be the worst for audio quality against anything out there.
Best I've found for "audiophile quality" on a motorcycle is a Sony X-series MP3 player (not Apple, they suck on audio quality as did the defunct Zune) piped through some musician's phones, or what they call as "Custom In-Ear Monitors" or "Reference Monitors" like the Ultimate Ears
(link) which have to be made from an impression of your ears and are pricey, like $1,200 up to $2,000 for the multiple-speaker units (Mine has 4 speakers per in-ear phone, UE-11). Even with an Autocom in the middle of them you will get amp background hiss, but it is only heard in silent spots. They have to be one of the best accessories I have used on the bike as they kill off exterior wind noise in the helmet and I can listen to them at a lower level while they still deliver the full acoustic range. No tinnitus after a long ride either.