Ok, so heres a quick prototype I made:
Again, not sure what can or can't be done, but:
1) I definitely think you should use the WiinerTag logo that you have on your site on the sigs. Makes it look cooler. (And I don't care about the name, I'm confident enough in my self LOL)
2) I made an example Mii using an online Mii creator (Google it) so again, not sure if this is something we can upload ourselves or you can somehow add a similar generator to your site. (Talking out of my ass on this one)
3) Not sure if there is some code that can be used to automatically add the game cover reflections, but it would be neat.
4) As for showing which loader we are using on the sig, maybe you can just make it show a small icon instead of the name? That way it won't take up so much space. (Example like a W logo or small icon for Wiiflow? U logo or small icon for ULoader? etc.)