I\'ve got a humpback... 
  tailpack that is!
 
 I won it from Performance Bikes for a rant that turned out to be their 'Star Letter' for Feb. It's not very big, but it's pretty versatile. Turns into a rucksack or a carry bag, big enough to hold a lid. You can get a conversion kit with all the magnetic doobries to turn it into a tankbag. That would be my favourite.
 
 For occasional use when you need to carry just a few odds and sods, use it as a tailpack. when you're two up touring somewhere with all the panniers and stuff on, use it as a tankbag
 
 Forgot to mention it's an Oxford thing, in case you didn't already suss that
 
 [Edited on 13-6-2003 by Jools]