Building cabinets isnt trim
I do this for a livin and cabinets are cabinets to be priced seperately from "Trimming out" a house. I think the builder is smoking crack if he expects it done in 4 weeks including built ins or cabinets. Maybe hes just extremely inexperienced . I can give you pricing that I use for piece work such as crown, casing,door installation etc. Outsourcing would be the only viable alternative to the timing issue ( Cabinets,builtins, etc. by others}. I do general contracting -large renovations and new home construction along with custom work for other GCs{very few}. If you work this out GET A SIGNED CONTRACT.