Your safest bet for a clean Bel is Mojave x lesser. No grey head like the super Mojave, no bug eyes like the super lesser.
As for prevelence of bug eyes, it seems fairly common, but I don't have any clutch data. I think Jerry had a few bug eyed supers, or maybe he knew someone who did...(his username is snakesrkewl if you wanted to pm him directly)
Here's the lesser Mojave http://www.worldofballpythons.com/morphs/lesser-mojave/