Years ago, there were several programs available for "automatically" generating XML code from a visual GUI, but none of them ever worked very well -- think "HTML code generated by MS Word in 2002 -- and none of them have been updated in a very long time, so they are not up to date with the current WoW API. Long story short, you shouldn't use them.
Anyway, I wrote up a (fairly) simple addon with a scrolling list frame for someone on the WowAce forums a while ago. If you ignore all the code related to looting and item icons and such, the rest should be relatively easy to understand and adapt:
http://forums.wowace.com/showthread.php?p=320619
You'd also want to modify the click handler to add an editing function, in addition to the current deleting function.