You might be able to cobble something together through DLNA which is what the Denon and WDTV Live both use. However not all DLNA servers are equal, most are general purpose and music specific ones like Asset
don't run on WD NAS.
Once you have your server set up you can use UPnP/DLNA controllers to act as the front end, one of the best ones is BubbleUPnP but that is only available for Android, there are a ton for iOS too but not sure which to recommend, Skifta is a popular free one.
Minimm is available for some NAS like ones from Synology, Netgear and QNAP that allow app installs.
An alternate approach is XBMC on an Android tablet.
* Install XBMC apk
* Go to music and add source, browse windows networks and select music folder on NAS.
* After it adds folder bring up context menu and scan media into library (this gives you more browsing options).
* Go into system settings->services->UPnP and enable look for UPnP devices
* Back in music section bring up context menu and select play using, any DLNA/UPnP devices might appear here.
So your effectively using the full XBMC as a controller and UI for media playback pushing it to the Denon and WDTV. However the catch is it may not work, the play using feature was only designed to work with other XBMC clients, support for other UPnP/DLNA devices is coming but probably not until the next version of XBMC or version after that.