When Howard Sherman, a coat importer, reached his 50s, he and his wife, Heather, decided they wanted to leave Thornhill and jump into the downtown real estate market. Immediately they spotted a niche. “There weren’t many high-end live-work properties available downtown,” Howard says. So they bought 241 St. Clair Avenue West, a dilapidated century-old house (carved into apartments) with three attractive features: it was in Forest Hill (South Hill, technically, but who’s keeping track?); it was cheap ($710,000 in 2005); and it was zoned residential-commercial. They tore the old place down and, with Kirkor Archi­tects & Planners, built what they hope will be the first of many home offices. The ground floor is parking, the second is office space, and the third and penthouse are for living (the Shermans have been there since last May)—complete with an elevator connecting the zones. Now they hope to sell it for $3.2 million and do it all over again.