Open Cloud means x86It really is that simple, for a cloud to be open and allow portability then you are going to need to have zero proprietary solutions, this means no z/OS from IBM, no Google App Engine lock-in, no Azure lock-in. The base platform of portability is the x86 machine.
Now you can argue that a Java VM could be portable if you have full JDBC libraries and the like, and I wouldn't argue too much so yes you could have an Open Cloud for Java approach. Theoretically you could do the same with .NET. The Platform as a Service play is however fundamentally a lock-in play in the same way as JavaEE vendors give you lots of specific libraries and features that only work on their platform, sure you can avoid those but a PaaS provider can make that rather hard.
Infrastructure as a Service is the most obvious place for Open Clouds to start and that means agreeing on x86 as the basis. It clearly can't be Java as MS are unlikely to sign up to that and IBM are highly unlikely to agree to .NET therefore the lowest common denominator is the virtual physical machine which has to be x86.
It would be good to see an Open Cloud for Java but can we at least agree that when its an infrastructure cloud that the cloud must be x86 based.