I looked on eBay for weeks. Then I had the fortune to talk to Mika'ele McClellan in LA who said he had an "as new" extra. I bought it from him as well as his book. It is out of print.
A WORD OF WARNING
The tablature in this book is not the same as you are used to seeing and will take some getting used to. Also there is no accompanying CD or Tape. The Leonard Kwan recordings you can find will not match the book exactly but it will give you an idea of what the master accomplished.
E nana, e ho'olohe. E pa'a ka waha, e hana ka lima.
The music and tabs were hand-written but done quite nicely. The price tag which is still on my book says $5.99.
The CD titled, "The Legendary Leonard Kwan; The Complete Early Recordings" may be useful (or these pieces on whatever media you had/have -- 78, LP, tapes).
The problem with the TAB is that there are 5 lines -- therefore each "string" is represented by a "space" not a line. (Also some of the numbers were a bit hard to read.) I just wrote out the songs I wanted in 6 lines TAB - it was easier in the long run.
The Hawai'i Public Library system has this book and it can be found in their public access catalog. Some mainland libraries can arrange an interlibrary loan.