Yeah, I remember reading United wanted to join as well. After seeing Sporting boss the tournament, I bet Benfica and Porto want to join to show off their own academies.
I'll admit I was definitely a bit concerned at first that a few of the teams from this year wouldn't want to bother with it again (like Basel, Molde, Rosenborg), but yeah, doesn't seem they'll have any problem getting to 24 for next year, and I would imagine 32 for 2013-14. It'll be interesting to see what they do from there, if they'll start to kick out poor performers for more prestigious names, or what.
Also, random, but I just checked the Portuguese league table out of curiosity, and Braga are in 1st. Wow. Hate them for all the diving they did against us, but fair play to them for being in 1st.