You start off as a human, but the artists aren't drawing a human as a representation.
Could that ever be an option - something like a "character creator", that allows for different body options? - I can imagine, it would be a hell lotta work - especially when drawing the different body modifications then, too.
Yet, I think doing a little bit of that over time, might eventually allow for it to be implemented. But, I wouldn't implement it before it's not almost completed then, since otherwise people will bother you about it all the friggin' time.
But seeing all the sexy characters and exciting body mod options in the game, really would make it exciting to see that, too. But, of course, also (partly) re-drawing some sprites and scenery images with the different mods could be a little too much then. Even though, I don't think people would mind waiting. At least those fans, that really understand the effort and work that goes into it (and which should be done with joy and love - since only then it really can be the most beautiful and "best" possible version of it all.)
So, the creative process is a fragile thing, I know - but whatever your "Muse(s)" is(/are), keep it happy and pleasantly "milking" those sexy, "creative juices" - 'always excited to see where it's going, especially with such intriguing and smart, yet subtle works like this.