Although I think Patrick is long gone I feel like spewing.
If selling to a small markets like farmers markets perhaps you should make many different versions to offer and see what your consumers want and then consider which ones to produce more of?
Also offer customized rolling pins. If they came to the small market in the first place then chances are good they'd come back to receive what they want/ordered.
As far as cracks and holes in the wood goes being fixed with a filler.
No way no how!
Filler in a surface used for food prep is a no go if you're trying to sell them and speaks volumes about the care you give to your product.
Wood is wood and you've just got to work around or with it's imperfections.
Eons ago a co worker said to me when I was pissed about a screw up with a product. "Hey it's only a piece of wood, Find another piece and start over".
On a side note, Don't use a finish on your product. If you feel you must then simply use mineral oil. It will keep the wood from drying out yet it will in time allow your consumer to use another finish in the future if they feel the need.