Ive never even really heard of bumpmapping appplied to reflections, but It doesn't seem TOO hard.
I have, and most modern hardware supports it... it's called "enviroment bump mapping". Try our 3Dmark2001 feature test that does just this, it has bumped shiny "alien" :)
http://futuremark.com/products/3dmark2001/?screenshots
[the greenish alien, left bottom corner... looks great when it's moving!]