Remap Super+arrow key to home/end

How about a combination of xdotool and xbindkeys, with a .xbindkeysrc like:

"xdotool key Next"
  Mod4 + Down

"xdotool key Prior"
  Mod4 + Up

(on my system windows key is bound to Hyper_L = Mod4)

Another (very cool) option if you don't mind using the mouse could be to use gestures. For instance on my netbook the End key is a pain to use (Fn+Pagedown, and hard to reach). I installed easystroke and set it up so i can just make a "V" like gesture and it sends End. For Pagedown, it's a down-up "|" gesture (begins to feel a lot like an iphone!)