You might be interested in the following related project. It includes downloadable source files which work on 10.2. I built it from the sources at the end of part 4 (the last part written so far), and it works ok as a simple text editor (especially after I hacked it by adding ".txt" as one of the recognized document types, besides ".html").
The series is incomplete -- this thing only edits black single-font text so far, though it'll also tell your browser to display that text as html (if the filename ends in .html) -- I hope the author will keep working on it.
Since it uses the Cocoa Document framework, it does some cool things that even BBEdit Lite 6.1 doesn't do, like notice when you rename or move a file in the Finder and update the open document window to match, and support the Services menu.
HTMLEditorX - A new beginning
By: Scott Anguish
November 28, 2002 - 04:15 AM
HTMLEditorX is a document-based multi-window HTML source editing
application. The goal is to introduce users to the Cocoa frameworks and
guide them through the building of an application.
- Bruce Smith
P.S. I like this Mike Beam series too -- I hope the author updates it for 10.2 and adds downloadable source/ProjectBuilder archives.