Took out comment about wondering whether same cmis api calls work in parallel, things are fine for me with parallel calls both using sockets/as3httpclientlib or in a non sockets mode (HTTPService / URLLoader)
It looks like the CMIS uses http methods not supported normally in Flex (unless you use sockets or add a proxy)
i.e. PUT, DELETE see in the spec for some things
Does CMIS plan or already have a way of passing the method as arg (like web scripts) ?
(answer from Dave via twitter: proposal is to support the same method override as Google data api)