Can you look at ceiling cassette units? Same ductless unit just in a different form factor for the indoor part, here's 2 options.
18000 BTU Ceiling Cassette Air Conditioner - Heat Pump - SENA/18HF/IC - Senville.ca
24000 BTU Concealed Duct Air Conditioner - Heat Pump - SENA/24HF/ID - Senville.ca