I found this really cute one today and as luck would have it I actually have the required ruler to be able to do it.
I won't even bother to say it will happen anytime soon, but it is definitely something I really want to make sometime in the immediate future.
Here is the link in case you want to give it a try:
If you do one please be sure to use the comment feature and send me a picture of your finished mug rug, I intend on picking out fabrics this weekend in between filling orders, who knows I might even be able to start one :)
I will drop some more links when I come across some more good ones, so keep checking in for more :)