My guess is that Google does not want to run afoul of DRM (Digital Rights Management) laws, hence the inability to Bluetooth tones. Having seen plain ordinary citizens fined many thousands of dollars over this touchy subject, I can just imagine what a legal field day would be had, and how costly it would be, if Google had to lock horns with the likes of the RIAA (Recording Industry Association of America) to satisfy your desires. Shame on them for not wanting to do this! ;-)
I get around this by creating my own ringtones, using an Open Source sound editing application that I have installed on my Linux-based PC, and then uploading the tones to a Ringtones or Notifications directory that I created on the root of my memory card, using the USB cable supplied with the phone.
Samsung r880 Acclaim/i500 Mesmerize
If I've helped you, please give me thanks. I'll do the same for you!