Much thanks for the feedback.

I think in this instance, another challenge is that the ruby source 
build provides more than the ruby1.8 package.  Just one example being 
libzlib-ruby1.8.

With this being a somewhat labor-intensive process, I'm now wondering if 
there is a way to automate it using ruby (the creation of equivs file(s) 
by automatically parsing the packages.debian.org site).

It seems they recently packaged up ruby 1.8.2-2 to fix the autoload bug 
which I thought was introduced AFTER the Christmas ruby 1.8.2 release. 
If this is correct, then it seems they're using the stable snapshot and 
I guess ruby 1.8.2-2 will make it into Debian 3.1.

Your warning was a good reminder of the dangers of equiv.  So, if we 
wanted to simply rebuild the various debian ruby packages with 
optimization flags, what is the most reliable approach?  apt-build or 
downloading the tarballs+applying diffs+tweak+build?

I'm leaning toward your suggestion of applying their diffs unless 
someone stats success using apt-build for ruby.