It sounds like the perfect use-case for Tapper.

There we have a scheduler that maintains HOSTS and QUEUES. Queues usually mean a test use-case (like "linux-stable", "linux-rc", etc.). You put test requests into a queue inclusive some "requested host features" spec, let the scheduler decide which queue next to choose per bandwidths and available hosts. Test requests can "re-queue itself" to create a continuous rotation of the use-cases.

Setting up Tapper with all features (as used in the OSRC where we set up machines from scratch to with other distributions and Xen/KVM setups) can be a bit tricky but you seem to be ok with using ssh.

See http://renormalist.net/misc/ for public material about it.

Tell me if you already found another solution. Else I could help you set up a Tapper instance step by step.