Some thing you may want to consider: (goes for everybody)
1) Maybe they are busy or already working on it.
2) Rendering takes really long, sometimes over an hour per render. So don't expect it to be done the same day you ask.
3) They've got a life too..
most of all:
4) Ask it nice.
and:
5) PLEASE don't use the [img] tag with such large images, put the skin in the attachments