Updated to note Imeem: Google will soon launch a search product dubbed “OneBox” that will better organize results around music artists and provide music streams from Lala.com, MySpace-owned iLike.com and other services — including full-song streams, according to one of my sources who’s seen it firsthand. That would make it a modest innovation in user search experience, but not a game-changer that will upset iTunes or compete in the mobile sphere as some early reports have speculated. So modest, in fact, that it sounds a lot like what Yahoo has been doing since last fall with RealNetworks’ Rhapsody.

We’ll know more when Google lifts the curtain next week, but for now color me doubtful that Google is interested in either selling downloadable songs or providing a large-scale free streaming service that would compete with Spotify’s. If Google were interested in selling content, it probably wouldn’t favor the incredible shrinking music business, and the economics of free streaming are apparently unsustainable. If anything, Google might buy rather than build, as it did with still-money-losing YouTube, but such a deal seems a long way off given the lack of anything close to a proven model in this arena. (Google, for example, wasn’t the one that bought iLike this summer — MySpace did.)

More likely, Google’s new product will resemble one of its other enhanced search products, perhaps a sort of “Rich Snippets” with full-song streams from its partners. A Google search for a musician usually yields YouTube videos and photos from external providers, but often includes links to a Wikipedia entry or an official site that direct the user away from Google. A better product could keep users around a little longer — all the better to sell ads to them — and could include a rev-share agreement for the stream provider. (Google already has a relatively well-hidden music search product that could also use a rethink.)

If Google has anything more earth-shattering than that to announce — such as a separate rumored Google Audio product that requires deeper licensing conversations with major labels and others — we’ll know soon enough. For now, though, this appears to be a relatively minor improvement on Google’s search presentation, a boon to Lala.com and iLike.com, and something of a blow to smaller streaming music providers. I’m expecting to hear more soon, and will update the post. Update: A source that asked not be named tells me that Imeem’s song streams will be integrated into the search results as well, although an Imeem spokesman would not confirm this. It remains unknown how many streaming music providers will appear in Google’s new search product.