From RockBandAide:

It’s been just over a month since a number of people went searching through the RockBand.com artist URL pages looking for future artist DLC. With the exception of EMF, all of the artists uncovered have arrived as Pro Guitar/Bass DLC, so don’t be surprised if Unbelievable appears in the Pro Guitar/Bass DLC announcement this Friday.

While this “hack” only works for artists that currently have no DLC, the latest round has uncovered only two gems so far (expect updates if more are found). While Heart has made a number of appearances in Guitar Hero titles, this find may signal the band’s first appearance in the Rock Band franchise. Here are the bands found thus far:

• Frankie Goes to Hollywood
• Heart

The two links for the band have quickly been 404'd, but the last time this happened (which is linked in the RBA article), all but one band have officially been released (EMF is the only band yet to be released from that list, I would guess we should expect it next week?) so I'm pretty sure these two bands will be coming to Rock Band in the near future.

I'm pretty excited about Heart, there are so many good songs from them, what about everyone else?

Better be Crazy on You.

I approve of Heart.

When in the hell is The Weight by The Band coming out?

Heart confirmed. Will be released in a few weeks but it's a single song and not a pack.