Who commits to five nines 99.999% availability?

Can anyone point me to a cloud hosting provider who will really commits to 99.999% availability? From what I’ve seen some offer this but only back it up with meaningless compensation if they fail such as refunding a months hosting fees which for any business which really needs 99.999% availablity will be out of propotion with the damge unscheduled downtime brings. The other catch that you often see is 99.999% planned availablity which means that they can schedule as much downtime as they like as long as the plan it and let you know in advance.

I ask this question because although i’m very much in favour of cloud hosting i increasingly feel that where clients really need 99.999% availablity they need to look at a hybrid solution which eiether combines your own hosting scaling out to the cloud which has been done succesfully or maybe ultimatley a mix of hosting over two or more cloud providers which as far as i know no one has really done on a large scale successfully yet.

So while contracts often call for five nines can the client afford that extra nine, are they prepared for the complications it brings and even if they are is it more of a target than something anyne will actually commit to in application hosting today?