@scottmoore After some noodling around this weekend, this is what I came up with.  This menu command launches a dialog box.  As you type in the Text field, the list browser becomes populated with objects whose names contain the given text, sorted by object type and defaulting to being selected.  As you type in the Replace With field, the Result column of the list browser will show you what the resulting rename will be, highlighting in red if a matching object name already exists in the drawing.
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