Well this is pretty simple, any carpenter should be able to do it.
First, Remove all interior finishes (including cabinets, electric and plumbing trim)
Second, remove all sheetrock.
Third remove all insulation, wiring, ducting, and any plumbing that extends above the walls.
Forth, support the existing roofing system in place with a jacking system.
Fifth, jack the roof up a foot.
Six, remove all wall framing
Seven, frame, stand, brace and sheathe new walls
Eight, put the house back together.
You should be able to do this for a little more than the cost of building a new house.
First, Remove all interior finishes (including cabinets, electric and plumbing trim)
Second, remove all sheetrock.
Third remove all insulation, wiring, ducting, and any plumbing that extends above the walls.
Forth, support the existing roofing system in place with a jacking system.
Fifth, jack the roof up a foot.
Six, remove all wall framing
Seven, frame, stand, brace and sheathe new walls
Eight, put the house back together.
You should be able to do this for a little more than the cost of building a new house.