have heard of oggplay before? it support random ringtones provided u have select the provided ogg file (forget what its name already, if not mistaken, random.ogg ) as ringtone. every ogg files in that folder will be played randomly each time ring.

problem:
1. slight start delay compare to normal wav/mp3/etc
2. using ogg file. need to convert.

btw, this software quite old already. actually the 2nd software installed on my 6600 after fexplorer, 30months ago lol