"is there some kind of meeting once a month in vegas were collectors can trade chips?"

The short answer is yes. I will let someone else gove more details. Here is a link to the Southern Nv. Casino Collectors Club.
Barry

http://communitylink.reviewjournal.com/servlet/lvrj_ProcServ/dbpage=page&GID=01017010550967500301337191&PG=01017010550967500301414323