Flexible TTS options

I've been wanting to do this since I got my HE, but haven't found a good option. When doing TTS, I want the ability to insert WAV/MP3 files, arbitrary delays, variables (like %time%, %device%, etc). For example, the speak string might be:

"%play= %delay=500ms% Back door opened."

I can create voice alerts in RM and do this on different lines, but it's pretty tedious when doing a lot of them. Does Message Central or any of the other TTS management options do what I want easily?

Take a look at Follow Me, can do most of what you want and a lot more.