Fantastic concept. I really like the direction you are taken it, then again I am fond of Incarnum in general so I may be biased. A couple things I'd like to ask though.

Weapon special abilities, how were you planning on doing them? You could make it so that the Soulblade itself has 2 essentia recepticles one for enhancement and one for special abilities, but then you would need to figure out how you could pick them. Perhaps when you shape the Soulblade meld you pick the weapon special abilities and when you invest enough essentia into the ability receptacle (2 points for +2 ability) it activates.

Any thoughts on adding an enhanced capacity class feature for the Soulblade meld? Even adding a +1 will let them to get to +5 without taking up a feat slot.

Lastly, the binds are an intresting way of handling the weapon function, but I think you could improve it. While the adding benefit each chakra gives is nice I don't know if it's worth closing off a bind and it's really not worth it for the sole sake of changing the weapon from 2h, 1h, dual wield. Especially when you can't change the type but once or twice a day. I know weapon flexibility isn't necessarily a huge issue, but it was nice as Soulknife to reshape my weapon whenever I wanted. It was mentioned early that the Incarnum blade had the blade meld and I think that would definitely be something to look at. They do binds for their blade meld that don't close the chakra to other binds IIRC.