I just started building a 16' Wa'apa designed by Gary Dierking. He has a great book which is shown at the bottom of this page:

http://homepages.paradise.net.nz/garyd/wa_apa.html

The book contains 3 boat plans. You do need to hunt through the whole book to get all the required information for the Wa'apa. The Wa'apa can be built with many options. It can be built as a proa or a trimaran; 16' or 24'; and it has many sail rig options. I am building the boat in two pieces. The book also contains a lot of info on how to make a polytarp sail for it. It has a nice small history of pacific ocean canoes. I think a lot of designers who sell plans for $110 but offer it all in a book for $22. Great for those who have little cash but are prepared to do some research in a book.
I bought mine at a great store called superbookdeals:

http://www.superbookdeals.com/cgi-bin/search.cgi

Mike