Alain, I think you will be surprised by the price when you add all fittings and rigging together. Marine equipment is very expensive (I personally feel that somebody are doing a x3 on their profits somewhere in the chain). Building the hulls are not to expensive, 4 sheets of 4mm quality marine-ply, some epoxy, cedar, glass and carbon. The real cost is in all fittings, blocks, sails, cleats, rigging, mast, lines, tiller etc. etc. Phill can probably give you some numbers in AUS$ if you contact him.
If you are on a tight budget (I guess you are, since you want to homebuild instead of buying?), my best advice to cut costs is to find a derelict beachcat locally which you can pick up for a song. Strip it for all fittings, blocks, rudders, pintles, rudderheads, rig, tiller, crossbeams etc. that you can use, and you have saved a lot of money. Do _NOT_ fix that old beachcat, just strip it and go ahead with your building, if building is what you want to do. Look around clubs and you will probably find something lying in the bushes.
I would seriously try to get a Superwing mast section for your Blade if you decide to build however. I think that makes a lot of the boats "feel".