... that way I could create a unique search form with an action that would display results for one blog at a time… or I could avoid displaying results from blogs I may not want to make available to the general web population.

Actually, I’ve answered my own request.

This is not a “feature” on the surface but it is possible.

The tag found in the search results page can be changed from ...

<?php show_search_results($weblog,$keywords,$criteria,$where); ?>

to ...

<?php show_search_results($anyblogyouhavenamed,$keywords,$criteria,$where); ?>

... and there I have it ... search by blog