LayOut does not yet have a “live” plugin API. But the API can create and modify .layout files from SketchUp.
(list of tutorials re:) Construction documents - general overall flow question - #4 by DanRathbun
A good programmer will cost not less than 2000 $ per week (likely more for the gurus.)
Something like this would take not less than 3 to 6 months (dependent upon complexity) perhaps up to a year.
So say 24k … 100k development.
Or you might piggy back onto Neil’s work. See where his project is at this time (it has a trial):
Extension Warehouse page: Extension | SketchUp Extension Warehouse
Gallery: Building Creator Extension (Demo Video)
Discussion: Building Creator Extension
When I say “piggy back” I mean perhaps pay him a bounty (fund) some particular enhancement that you need.
@Neil_Burkholder (ping)