I have worked a bit on a Mellotron-choir patch for the Virus KB lately. It has some certain Mellotron-feel over it, but it could need a some more high frequencies, but thats difficult to do due to the filter settings. Here are some samples of it:
http://home.online.no/~per-kr/Stuff/..._TheBeyond.mp3
http://home.online.no/~per-kr/Stuff/...r_Oxygene2.mp3