I've been looking into the build for a while myself. If you're prepared to give up live for some years while you build it part time along the daily grind, you can probably do it. You're looking at no kite, no surf and and most likely some dramas with your mrs.
While it initially appears to be a fairly cost effective way to get your hands on a cat, after adding up all the components, build material, rigging, nav equipment and all other toys you may want/need to have to be able to live aboard for some time, you get to the price range of secondhand cruising cats, if not more. And that's not considering the time spent building it.
Example:
http://www.ebay.com.au/itm/Dean-400-Catamaran-in-Sint-Maarten-Caribbean-/221255615327?pt=Sailboats&hash=item3383dcc35f&_uhb=1 (..it's got a decent bridge clearance

)
Another option is to finish a project someone started but had to give up:
www.boatpoint.com.au/boats-for-sale/boatdetails.aspx?R=14423908&Silo=Stock&Vertical=Boat&Ridx=10&eapi=2www.boatpoint.com.au/boats-for-sale/boatdetails.aspx?R=14005531&Silo=Stock&Vertical=Boat&Ridx=14&eapi=2(i'd go for a Schionning if I would build)
I'd say keep kiting/surfing and keep your eye out for something that would suit you, ready to sail. The time building could be spent sailing and kiting/surfing some of those atolls in the south pacific. But then again, you may be happy building for some years.