the medly idea is a good one i think, because you can showcase many different things you can do. most of all if u make a mistake keep playin, you never know they might not notice it. :p
as long as u make the different bits flow into each other it should work well. u might have to change the keys you have learnt each song in to make it flow more but that aint very hard on guitar, just move up a few frets.
