I was just at Walmart (Canada) and in the office supplies in the pencils section was a Staedler metal 2 hole sharpener. It labelled one hole for graphite and one for colored pencils. I bought one for my son and it was $ 4.27 thereabouts. I found one on Amazon that looks just like it.
Amazon.com: Staedtler Tub Pencil Sharpeners double-hole sharpener: Office Products: Reviews, Prices & more
I tested it on a prismacolor and did a very good job. The hole is slightly bigger and the pencil wiggled in it but sharpened very nicely. My son severely warned me not to put it in the graphite hole, but it would have fit in that LOL. The coloured pencil hole is not as big as a make-up one but I tested a Lyra Metallic pencil ( which has a 4mm lead and a larger oddly shaped barrel ) and it fit and sharpened well.
I might have to go back to Walmart and buy one for myself