You might want to check out the four-panel door that David Marks did on
Wood Works available at DIYNet:
http://www.diynetwork.com/diy/shows_..._26952,00.html

He did this in jarrah with loose mortise construction if I recall.
Also, I think he did his in 1 3/4" construction, but 1 3/8" is very
common.

-Stormy.