Here are my only two sources for random terrarium plants.
First would be to either post a Looking for thread or just check daily. They have a good amount of new posts a week and the good stuff goes fast.
http://www.dendroboard.com/forum/plants-supplies-classifieds/
Option B would be to contact
http://www.cloudjungle.com/ and hope he is still selling/trading. I know a few years ago he was trying to reduce his collection size so I have no current info.
We also have a few people on the TF Forums that frequent the dendroboard and grow these plants, since I don't like random PMs asking for this and that I just can not give out names. Maybe post a trade up here and see what happens.
I'll check and see if I have any growing when I get home, I've received a few cutting over the years but they never interested me so I just tossed them into a terrarium and forgot about them.