Again, I stand to somehow disagree with so many brilliant minds in here, so I apologize in full respect.
From a theoretical standpoint, BPM and Cloud are orthogonal. BPM is a business practice and Cloud is one of its (possible) deployment models.
From a practical standpoint, they are as orthogonal as Media and Internet are now. Which is not at all. They also used to be perfectly orthogonal: Media was the Content, the Internet was one of its (possible) distribution models. You bought Media via the Internet because of the superior distribution.
That is, until the Internet BECAME the Media. The Internet is not a distribution network anymore, because it has completely CHANGED the way we consume and get influenced by content, and has CHANGED the Media business model at the same time. We don't buy content (music, books etc) anymore because the Internet is encouraging us now to stream it, to rent it (unless you believe you own those books on your Kindle), to lease it.
The Internet has the ability to morph and disrupt any intangible asset. As a result, the Internet has democratized, in turns, information, knowledge, wisdom, style, wealth. So why would BPM (a part of a business model that is concerned with optimal wealth creation) have a different fate?
Cloud will completely CHANGE BPM as a business practice. Yes, there will always be on-premise deployments (for integration / security / confidentiality reasons), but what about the VAST majority of small to medium businesses that could never afford a complete tech stack (servers / middleware / software / consulting) just so they can have a best practice in procurement, for example? Nobody wants to buy the whole cow when they only want to drink a glass of milk.
It is already happening, although the beginnings are shy and laughable to many experts, so for now it all depends on how generous you are with defining current software as BPM technology. In my mind, as long as you use it for business, Evernote is a BPM technology. And there are countless examples: Dropbox, Google Apps, Tasker, IFTTT, Basecamp, Smartsheet etc.