Check out Fine Homebuilding issue #168 (December '04/January '05), page 86. This article, titled "Custom Doors, Done Easy", describes a simple, sandwich-style method for building larger, thick doors. As the author, Scott McBride, states "Building a door in layers gives the look of traditional joinery (stiles and rails that meet with mortise and tenon joints) with less of the fuss. The key tool for this technique is the pocket-hole jig . . ." "Strength and stability are important when you go beyond standard door sizes, and the layered constructions of my doors makes them strong, stable, and heavy." I plan to use this technique to build several oversize doors for my whole-house renovation. Good luck with yours.