That's a great idea, and would be very easy to make. At least one of the fabrics that is shown in the link you provided is a pre-quilted fabric - I know this b/c I used that same fabric to make a weekender tote. So you could go that route, finish the edges w/ binding and put on Velcro - done in under an hour!
Here are links to others with tutes:
http://kaelynscreativestudio.blogspo...me-covers.html
http://pinwheelponders.blogspot.com/...kings-for.html
http://www.scarletquince.com/elbow_glove.php