Ron,Scott (and all),
These movies are available on iTunes. Not all Paramount is, but most of their catalog is available.
Is it just Vudu is treated as a separate infrastructure so these kinds of sales are limited to their distribution?
Think of iTunes, Vudu, Amazon, etc. as separate storefronts to purchase films. Each storefront has its own transfer of the film on its servers. Some studios participate in a system called Movies Anywhere, which will propagate purchases of films from those participating studios to your digital library at each participating storefront -- you have separate digital libraries at each storefront where you have an account. Unfortunately, Paramount, MGM, Lionsgate and some other studios do not participate in MA. So, anything purchased from one of those studios will only be available in your digital library of the storefront in which it was purchased.