While in Taipei a couple of months back, I walked past the Futai Mansion several times, but didn't have time to go in.
According to a Taipei Times newspaper article:
"Built in 1910, the Futai Street Mansion was originally used by its Japanese owners as an office. In the following decade, about 100 commercial buildings were constructed on Futai Street in the area inside the North Gate. The Futai Street Mansion is the only commercial building from that time to have survived.
Although small in scale (about 156m2), the two-story building has great historic value and was designated as a historic building by the city government in 1997. The mansion’s curator, says the building has the style of the Japanese Meiji period with a strong European flavor and was unique because of the materials used to construct it.
The arched pedestrian arcade was made of stone... and the arcade ceiling was made of Formosan Cypress and is diamond-shaped. The outside wall on the second floor was made of stucco faced with fine gravel. The roof truss was made of wood in the Mansard style and the steeply slanting roof was covered with diamond-shaped copper tiles. The three dormer windows on the roof provided ventilation.
During the Japanese colonial era, the mansion was used as an office by the construction company and then by a wine importer.
After the Japanese surrendered in 1945, the Chinese Nationalist Party (KMT) government took over the building and turned it into a dormitory for high-ranking Ministry of National Defense officials. It was eventually vacated in 1998.
Three years after the building was designated a historic site, a fire completely destroyed the building’s wooden structure and scorched the stonework. A one-year, NT$39 million (US$1.18 million) reconstruction project was completed in August 2007 and the building opened to the public in April this year.
The first floor now houses an exhibition room and a cafe decorated with the work of local artists, where visitors can enjoy tea and snacks while listening to old Taiwanese music.
Climbing up the wooden stairs to the second floor, there are two exhibition rooms, one equipped with a large-size electronic book detailing in Chinese and English the history of Taipei City from 1600 to 2007."
Externally it's very attractive. Here's a flickr.com phototream with photos of the mansion, starting with one that shows how it looked prior to restoration.