Paul, while I admit the only thing I know about the H-D Road Glide's stereo system is that Motorcyclist magazine mentioned how much they liked that bike's sound system in their recent comparison test between it and the new Honda F6B Gold Wing derivative, I have taken the Victory Cross Country for a demo ride and was quite impressed with its sound system. Plus, the storage capacity is a bit larger on the Victory Cross Country than on the Road Glide also.
And so, I'm not really sure why you included mentioning Victory in your statement here, as I believe at least that motorcycle company has your concern covered.
(...though I agree with your assessment that for the last few years, Bloor's boys have missed the opportunity to make the T-Bird into a viable full-on retro Touring Bagger alternative to these H-D and Victory offerings)
Actually the Harley stereo is nothing short of horrible but I install killer systems starting at $1000 and leaving the customer with $700 dollars of goods on ebay. Victory could compete but chooses to place spaceship styled bikes up against the industry standard. I think that the Cross Country may be getting there, but that whole Vision thing baffled me. The market was already there and trying to take it in a completely different direction wasn't happening. Victory shot themselves in the foot. Many Harley riders care little about storage space,some have me installing amps and subwoofers in the area that they have. I wouldn't do this to my own bike but that's where the market is. There is an entire aftermarket catering to Harley Baggers, I believe that they would make parts for some other company's version but so far nobody has stepped up. I'd love to see Indian enter that market since Triumph seems reluctant. Sadly, I think that the Thunderbird is the perfect platform for just the bike I envision.