What if you did the read and used SoundForge to post-process your voice ever-so-slightly to keep the acting but to make it 'not you' so you can enjoy the experience some more.
Also, if you DO decide to redo alien voices maybe some of us could help out with that as A) it would save you from having to do all of them, B) those would be 'lines' could be trimmed or sped up/slowed if need be and C) it would just be fun!