turning vacant land into strata units

I am currently looking at a 3 bed house on acreage IN town in a fast growing NSW country town which has the potential to be re-developed into 5 or 6 strata-titled townhouses. I have checked the zoning with council. Trouble is that because of the vacant land component in the purchase price, the place will be negative geared for a bit - and we all know that negative gearing sux the big one! Although, agistment for livestock is an option to help cover the interest bill...
I am however still considering this one, as the profit post development may be HUGE!
Has anyone done this type of development before?
How can I accurately estimate development costs before actually paying the professionals to do the work??
A bit of a "how long is a piece of string question", it's a pity Jakk doesnt post as much these days, the man from Droiun could really help here!

Anyway I am doing ( in the weak sense of the verb doing a 3 unit development now.

All up costs for construction, fees, interest, consultants, taxes, bribes to council members :), bla bla is <$1200m2 for 3br units, lets say you have 6 units each of 135m2 then 135*6*1200 = $936K for construction. I would suggest this is more in the above average price range than below average.

The you may be able to find bulk builders at $700m2 and if you invested your own time and energy running around you could cut non-construction fees down to <$50K. 135*700*6 = $567,000+$50K= $617K.

Naturally since I have choosen the developer path, I think development is the most logical way forward in IP investment, dont take chances with prices going up, create weath yourself by adding value! In many ways I think I have to work 40~60 hours a week, get the tax betten out of me, put up with all manner of crazy stuff typical of a big organization, so I can take home per year, less than I expect to get from one development. After 15 years of solid wage slavery, I have to get my mind off thinking that money is a result of earning it by the hour. With development the effort to reward ratio is much higher, however new issues such as the project management skills ( I have a bit of this), capital and cashflow management and risk management become critical success factors (so I am using professional help).

Livestock on 3acre's? Is there fresh running water on demand (ie a trough with automatic filling system)? a loading ramp or some way to get the animals on/off trucks...3 acre's isnt much for running livestock, a couple of pet horses maybe.
negative gearing is OK if you can sustain the cost until you receive the profit.

And you can always look at agisting horses rather that cattle....

Most importantly, is there a demand for townhouse living in the town?
Is the location right for the type of housing?
What are the building costs likely to be?
Is the council in favour?

Is there a demand for agistment in the town? (otherwise your holding costs may be higher)

As always, if the numbers work - it sounds like a good opportunity!