Not able to complete Pearl Jam on Expert vocals, I decided to contact Harmonix support to see if they would make a slightly easier challenge for those who missed out / can't quite make it.
They agreed, and let me know today (25th Mar 2013) that they'd "fixed" it :)
I just completed a Battle on my own on medium vocals (took 45 mins-ish)
It's the same 9 on disc songs, but you can play any number of instruments (inc solo) and on any difficulty. No saviour / overdrive, but that should be fine :)
To get to the tour: TOUR -> LOCAL TOUR -> (create/select your band) -> (join in on your controller and press Start button) -> BATTLE OF THE BANDS -> Through the Decades Battle (Thanks to
lightsup55 for the amendment :)
Songs for "Through the Decades" battle (valid for 8 years):
Pinball Wizard
Ramblin' Man
Let There Be Rock
We Got The Beat
Livin' On A Prayer
Alive
I Was Wrong
The Middle
That's What You Get
By the way... it should be NOTED that the achievement unlocks AFTER pressing the green A button (green fret button on guitar / tap green pad on drums) to "FINISH SETLIST" at the end of the last song. (Thanks to
lightsup55 for the amendment :)