I am not completely done with my kitchen but it seems to me that some things are better done by the "factory" and some can be done just as well (and cheaper) after the fact. I would think that roll out shelves would be one of those things to have done by the factory. My custom made cutlery tray was done after the fact and it's one of my favorite things in the kitchen (oddly enough)!! And it was only $35. To have it done by the cabinet company was going to cost wayyyy more.

Our amazing cabinet maker included custom drawer configuration in his pricing. I mapped out my utensil drawers on grid paper and he built them to my drawings. All my lower drawers have peg bases. I added dividers for lids in the pot/pan drawers, for the plastic ware drawer, for my coffee prep area drawer, etc. He is amazing, and we are so lucky to have found him. I would definitely get a quote from the cabinet company as well as after-market. Good luck!