After much searching, I finally found the base pattern I used for my Hogwarts fingerless mittens. It can be found here. Basically, you want a fingerless mitten pattern with stockinette stitch covering the back of your hand. Although I haven't tried it, this pattern looks like it would work really well also, maybe even better.
Knit the fingerless mittens in the base house color. I used Red Heart Claret for Gryffindor. Then use duplicate stitch to add the crest in Red Heart Gold. Here is the pattern I used
The toughest part was centering the crest on the back of the mitten. I remember marking and counting out from the center many times till I got the placement right. Oh and I remember having to be careful with my tension in the duplicate stitch. Too tight and it puckered, too loose and it looked funny.
There you go. Have fun and I would love to see the finished products!