I would think too many veritables involved to even guess. Location, amount of remodeling, quality of materials and labor cost all would vary. Top notch shops get $$$$$$$ for trailer upgrading.
WBCCI 10656 Southeastern Camping Unit
Associate European Unit
2006 Safari LS 23 ft
Formerly 1964 Bambi II
"I got a fever and the only prescription is more cowbell"