Thanks, what server do you guys play on? Is there a strong community on it?
I play F2P 20s, mostly on Aerie Peak US, very strong community on both factions, but this might no be the thing for you since it's a bit different from traditional twinking.
Some people are frustrated at 20 since you get people like someone who posted above rolling 24 for reasons not everyone might agree with, but you also have very nice people at both 20 and 24. While Kilda, who also posted above, plays EU, he is one of the really great people at 24, and there are more like him.
The F2P forum on TI is rather supportive and one of the brackets most well stocked with guides, if you want to have a look around. There are plenty other populated servers of course.
If you're interested in 19s, there are a lot of guilds on Bleeding Hollow, you will again find other populated servers if you have a look around the forums.
I'm not sure about other brackets, but each bracket has a LFG section, so you can see who is recruiting where. ^^
Good luck with your own guild!