Zeppelin

Genesis w/ Pete, Phil and Hackett (but don't let Phil write anything)

Brand X--speaking of Phil Collins

The Bears (Adrian Belew band of the '80s)

T Heads

Po-lice, echo the comments regarding Sting's testicles

Shoes

The original Funkadelic (not the P-Funk allstars)

Spinal Tap

And R.E.M. with Bill Berry

BTW, the Replacements did  re-form to an extent for some new tracks.  I doubt that a tour is likely, but the $$ must be calling to all of them.

And I would have said the James Gang, but just learned they are touring this summer.

And for a new category, Bands who should just freaking stop it already:

The Beach Boys --how can you have the Beach Boys without a single Wilson brother?

Journey--they've replaced the singer who replaced Steve Perry.  How sad is that?

Goo Goo Dolls --And you thought Sting's loss of testosterone was bad

Styx--Another "replaced the guy who replaced the guy...." scenario

Soul Asylum--Their new stuff sounds just like recent Collective Soul.

The Who--call it "Pete & Rog", but don't call it The Who.  The Who died with Keith and is completely gone after the loss of the Ox.  The new music isn't bad, but it's not The Who.

The Eagles--Farewell Tour 1?  Infers a Farewell Tour 2...and beyond.  Money grubbing arse-holes.