http://www.travisbeanguitars.com/files/documents/US3915049.pdf
^ travis bean patent description/drawings
as you can see beans have a few channels routed below the fretboard to help reduce neck weight. in general they are considered to be more stable than the kramer 'T' shaped neck.
i have to admit i mis-read your post above .. i thought you were saying all aluminum neck guitars needed or have truss rods. now i realize you were talking about the neck you're building (right?). looks like a cool project, can't wait to see how it turns out!
The aluminum neck needs also the truss rod. Despite being made of metal the neck tends to bend under the action of the tension of the strings, like a wooden one.
travis beans and electrical guitar company (current aluminum neck guitar maker) don't have truss rods
listen to drunk-n-darth maull!
don't change a thing on that thing! if anything, build some telescoping supports into the guitar like a tripod that support it while playing or something. and hook us up with the video , yo!