I had wanted to find something that gave a permanent conditioning effect like henna would, but without the color, and I know that tons of other people asked for that too. What about making the henna dye demise, and THEN reaping the benefits?

Wikipedia says probably not
The dye itself, Lawsone (2-hydroxy-1,4-naphthoquinone)/hennotannic acid, is what reacts with the keratin (protein) in your hair, binding to it and creating that beautiful gloss and shine. So if that part itself demises then there will be nothing to stick to your hair to create that conditioning effect.
...I think. Of course, there's that possibility that the molecule that Lawsone degrades into also is beneficial to hair, but probably not (the Michael addition reaction needs really specific substituents on the molecule). I'm guessing that in people that have had their intended results, the dye demised enough, they may have had darker hair, and it had a less effective conditioning effect (though that may not be able to be noticed, if we way OVER condition the hair with henna anyhow).

Just some thoughts. What do you think? I just want to get a clear-ish answer about this, haha.