iTunes Match is the closest I've gotten. I pay for the upgraded storage and its enough to store my entire music library. Anywhere I go I can listen to anything I own with no delay (assume a decent network connection).
Bonus benefit of iTunes Match + Google Music is that I can redownload my older iTUnes songs DRM-free so the uploader will pull them in.
(Source: I have a US iTunes account and I'm living in Germany)