I put the title in quotes because I have no name for it, but that's how i think of it. :)
After battling with custom solutions with templating on our Aolserver 3.4.2 installation, I created a small tag library which mimics JSTL. For those of you who haven't used JSTL, these are tags which provide a level of convenience in terms of doing switches/conditional logic etc, completely on the display side. These helps with removing those tiny little template files from your system, or hardcoding the html in the tcl itself, or trying to do crazy template manipulations from within TCL itself.
Because I'm too lazy to create a project on sourceforge, (and it's really a small code base) I'm providing a direct link. I would consider this 0.7 if I had to be formal.
I'm assuming as part of the Aolserver/ACS family you have implementations of exists_and_not_null and empty_string_p, but just in case you're pure Aolserver, I've included those as well, but commented.
Have fun experimenting! There is a test .html page included which demos the functionality.
http://www.ivanlazarte.com/offsite/astl.rar