This thread got me wanting more info on the subject of chloramines. Here's a link to a fairly good read. No idea how reliable or factual, but seems legit (Citizens Concerned About Chloramine, San Fran Bay Area, Cali) . Scary stuff actually, both chlorine and chloramines. Chlorine does seem to at least have the advantage that it will dissipate on its own if water is left standing in an open container for a sufficient amount of time.
According to one quote in the article, the RO membrane does actually remove one component of chloramine after the carbon stage.... and a DI filter would work as well, part of it anyhow. I think most of us use mixed bed DI media, cations and anions. The cation part will remove ammonia.
"To remove chloramine, an extensive carbon filter (to remove the chlorine part of the chloramine molecule) followed by a reverse osmosis or cation filter (to remove the ammonia) is necessary."
http://www.chloramine.org/chloraminefacts.htm