I would imagine the prices vary regionally and depending on whether you have a large boatyard do it, or someone with lower overhead. The boat you're looking at sounds like the same gelcoat situation I faced.

I hesitate on the "does not require a lot of prep" condition, because it's all about prep and even a smooth hull is gong to need to be sanded, and if it's gelcoat it will need at least two sealer/primer coats with sanding between. I've been told gelcoat is too porous to be painted directly with a topcoat.

The prices I was quoted from 3 vendors ranged from $15-20k for my three 39-foot hulls, which are relatively low freeboard. I would guess a 40-foot monohull would cost $10-15k. If you email me privately I'll tell you what I actually paid, with "extras" (cabin top stripes and white stripes).