Something to keep in mind is that you need to pick your location very carefully. These units have been on the market for years.
http://www.realestate.com.au/property-house-wa-kewdale-112510615
Mind you, they are over 55s only, so that may be a factor. Originally listed in March 2013 for "from $445,000" then dropped to "from $399,000". Now listed as "offers". Not sure if they are ever been lived in.
Agreed. I think by having them as over 55s you really reduce your market though. Single Bedroom dwellings can be sold to anyone so instantly your market is WAY more - first home buyers, singles, divorcees, people with fur kids, retirees, downsizers etc etc