I like the idea but its way too long and too much of a commitment. This conversion would take half of a character's pre-epic levels. Mythic examples, I can think of, even lichdom accomplish this is a much shorter time.

What would happen if you, for example, charged 10% exp of each new level and confined the changes to purely physical ones? No BAB, No Skills etc... Honestly I can't imagine how morphing into an animated object gives you better combat skills.

Sigurd

my 02