*** UPDATE ***
Issue 1: With the upgrade to firmware 1.08b, the upnp server refresh is almost instant

any new, modified, or deleted files on the DNS is instantly reflected on my XBOX 360.
Issue 2: To begin, my folder structure on the DNS is as follows:
Volume 1
-> Music
-> Videos
-> Movies
-> TV Shows
-> (name of show)
-> Season 1
-> 1x05-(name of episode).avi
I've determined that from the root of my videos folder, the XBOX 360 will ONLY play videos if the path/filename length is less than or equal to 81 characters in length.
As indicated in my previous post, #35 in the 1.08 release notes says "35. Improve filename length support in UPnP AV." So I'm hoping this won't be an issue when the official production release is completed.