As it turns out, MOST web servers don't place a limit on post data. Not even Apache. However, PHP does put a limit on post data (which, as you've already stated, can be adjusted.)
CF Server, as it turns out, does have a limit (regardless of what web server it's using) that is defined by the Java Heap. In CFAdmin, you can adjust the min and max java heap size (1024 = 1Gig) to whatever you require.
This is different from CF "Post Limit" which is a limiter on the number of form fields that can be submit in a single post (in CF10 this is default 100).