Is Installed-Software-as-a-Service (ISAAS) the Next Software Packaging?

SaaS Solutions Coming to an Enterprise Cloud Near You

I have recently noticed a few cloud application companies that are starting to port their solutions to multiple clouds — with Amazon, Rackspace (and other OpenStack providers), Azure, IBM, HP, and Profit Bricks being some of the targets.
The idea is for their application stacks to be closer to the other applications and data that their customers already have on the clouds (note that this is the opposite of the approach taken by companies that are helping loads and data be transferred from one cloud to another. In this case the entire software stack is set up in multiple clouds more “permanently”).
I have also noticed that these companies are starting to pitch enterprise customers that have built their own private clouds (mostly on VMWare from what I can tell) on the idea of moving the vendor’s stack onto the enterprise private cloud with the software vendor tunneling in to perform maintenance on the stack. The pricing is still subscription pricing and the software vendor maintenance.
It is not at all widespread at this point, but I am noticing it more and more as I talk to expansion-stage companies. I would characterize it as software-as-a-service that is installed on an enterprise cloud.

Is this Installed-Software-as-a-Service (ISAAS) the next evolution in enterprise software packaging?

I have asked a few enterprise data center heads this question and they seem to be open to the idea.
What are your thoughts?