In G.E.CK for Fallout 3 I was able to change the chameleon ability aka stealth boy to share the shadder for invisibility at 100%. But I do not see a way in the Oblivion's Construction set. How would I go about changing Chameleons shadder to show my character as if they're invisible even at 100%? So my character will not completely disappear when chameleon is at 100%?

You may want to check the Wrye Bash tweaks. There is an option to change the Chameleon effect there.