We recently won a tender to build 104 townhouses. These are upmarket luxury townhouses. Our stage one price which consists of 13 townhouses was around $192k per dwelling (average cost). However, these town houses where 185 and 205 sqm in size.
Generally, the per sqm rate on smaller units will be a bit higher as you have less open space and construction cost for open space is a lot less thus bringing the average cost of a larger dwelling lower.
Another factor that impacts on prices is the number of townhouses, generally the greater the number the lower the cost.
I hope this gives you some idea on estimating your cost. When it comes to tender stage I will be happy to submit a quote.