if you haven't decided what you want for Christmas, it's not too late to decide. Get yourself a Dremel Stylus, you won't regret this! I recomend this over any Dremel because
-variable speed 5,000 - 25,000 RPM for control
-docking station so you hold the lens with both hands against the rotor instead of one hand holding the lens and the other hand holding the vibrating device
-wireless if needed
-stays charged while at use on docking station
-no memory loss battery Lithium Ion battery
-Dremel can be held 2 ways or just leave on dock
also, don't forget these other tools when cutting your custom lens
Air duster - don't ever wipe the dust with a cloth or you can potentially scratch the lens
Disposable gloves - make sure it is snug fit. Avoid touching the lens with bare hand and minimize the dust on your skin
Marker - this one is more of a personal preference, the better you can see you outline, the better you can cut.
Brush- for cleaning up
Dust mask- disposable and cheap
Painter's tape - Make sure you get the LOW TACK, I think 3M's wallpaper tape is the best. This is just to slap on your lens for protection. (other methods can be used such as Saran wrap?)
last but not the least- Oakley clear safety glasses -you should have one already! I prefer the M-frame/Half Jacket for side protection. Don't get these cheapo ones -lol
feel free to correct my method/recommendations if you have a better suggestion