Come to think of it, the host doesn't really need to innately be an animal, humanoid, plant or vermin if there's a template or effect that can change its type to any of those... although this is reaching into the realm of impossibly complex, there have got to be some creatures with size huge that aren't physically so big or bulky, which could be used as a host for a medium elan made to qualify for the template, right?
I'm attempting to make an elan character that completely embraces the concept of becoming an aberration, but I don't want to go with the route of becoming a pseudonatural creature. What I'm really shooting for is something that's freaky.
Any ideas?