If I was in your shoes I’d probably build my own hypervisor box and rent colo space for it. Strictly because your requirement to migrate VMs to your own system later is more trouble than it’s worth.
I don’t know for sure but I’d guess you would pay less for colo than renting someone’s server for a year or two. Renting bare metal is stupid expensive.
But what if someone hid a Bat’leth inside one of them?