Winmodify
English is not my native either, I am Brazilian and speak portuguese.
What I undertood from your words was something like..."if you want to do us a favor, do it at your own risk, because if we don't like it we will not use it" and that came very badly to my eyes.
I allready did jobs for many different companies, really huge ones and others very small, I am used to see many different aproachs. I allready have many workes aprooved in the first version I made and also already made templates during one hole month to please a client, so this is not a big deal to me.
About the lizard thing, since your site is something for people to customize their desktops, I just thought that you could use something very unique, something that just remind the user to your site, if you use a lizard, it would not be original and could confuse your user....btw, I like the mice idea. In fact, I like it better then a lizard, it is more releated to computers. 
What I suggest you is, don't be so straight or you will have the risk of discourage any possible candidate to help you. There are some things that you can think, but you can't say. 
