That could work. I was thinking of "ultimately" as an adverb to "replace" (and split that infinitive), but your construction makes it an adverb to "to be" (ie "is)... but should "intended" be part of the extended verb "to be", and therefore does "ultimately" then split that infinitive instead? My head hurts.
I still think "is ultimately intended to replace" has a subtle difference in meaning from "is intended to ultimately replace" - is it the intention or the replacement that is ultimate? I say it's the replacement.