I have some experience, I experimented and made my own mutton sleeves for my Chibitalia cosplay in 2011. And I have plenty of plain white cotton to experiment with.
I had been googling lantern sleeves for a really long time the past 24 hours and basically got nowhere so I'll take anything you can give me @.@
Allen Walker and Chibitalia will be seeing you at AX 2012 ;D