I dont know if this has been tried but have you thought of something alonge these lines. setup your dremil in a smililar mannar as they did in this thread
http://forums.procooling.com/vbb/sho...&threadid=5270
but instead of making the x shape that they did, kinda grind down the top of it a bit then just make parallel channels like cathar did. anyway it might be worth a try or if someone already has done it post your performance here.