Yup it can be done. Now how hard will it be? That I cannot tell. To my ears it doesn't sound too complicated, but it will requiere a very well structured code and of course, some coding experience :P Making this your first ever program might be tought...
If you're interested in trying to code it yourself, well here a links to some cool tutorial, and info about wow add-ons :P
WoWWiki, your best friend. Has a list of all the events and functions in the WoW API
http://www.wowwiki.com/Interface_Customization
A very cool XML tutorial.
http://fara.webeddie.com/frames/
Lua manual, the language used in add-ons.
http://www.lua.org/manual/5.0/
Good luck!