Interesting blog on the Beeb about expanding the 6N to include the likes of Romania and Georgia.
I love watching the WC because of smaller teams like that, and I really think that if sports like Rugby and Cricket are determined to expand the game, they need to allow the smaller teams the chance to play against the bigger teams - it's the best way for them to improve. Look at Italy - their improvement since they joined the 6N has been immense.
My vote would go towards having a second 6N of smaller teams, which runs concurrently with the main 6N, and then have a Promotion/Relegation system where the top team and bottom team of the respective divisions either swap places or have a play-off to decide. It would give the teams in the lower division something to play for, and a kick up the arse for the underachieving top tier teams.