Yes, the method hari suggests works - I use it to play an Internet Radio stream each morning. Start playing, set vol 20%, wait 1 min, set vol 30%, wait 1 min, set vol 40%, wait 1 min, set vol 55%, wait 3 mins, stop media.
The delay plugin is interesting, but perhaps it could be made somewhat more flexible? Start with it intercepting and preprocessing events, then in the vein of the GSD, allows you to set up "rules" (like the command Ruby snippets) that allow you to insert Ruby code that execute on reception of the even, and do whatever you want including delays, but just about anything else as well. Then this code can delay the event, bifurcate the event into multiple separate events and send them at a time of its choosing, even modify or morph the events into other events.
So the plugin can be used as a Generic Processing Unit that hooks into LMCE's event system to receive timed or triggered events, and processes them into whatever you want, then sends them on their way - and all this without having to right a new C++ DCE device specific to purpose... just like GSD for communication with physical devices....?