Ask HN: Cloud providers offering custom kernels, booting from MBR

I'm interested in compiling a list of cloud providers which offer raw disk access with their virtualization. My limited knowledge on this topic shows that at least KVM provides the ability to boot from an MBR, permitting one to install any custom kernel and operating system at the discretion of the user, with no restrictions whatsoever.

I'm looking for providers which allow you to natively install any MBR, kernel, and operating system you want from scratch. I want to exclude providers that don't natively support this setup, where the only way to obtain the result is to jump through the hoop of having to install an initial operating system in order to run a shell script to "convert" to another kernel/OS.

I'm aware of only one provider that provides this kind of access to the virtualized boot disk, such that you don't have to choose from a select list of supported kernels. I'm not referring to AWS; if it's possible to drop any configuration in place without having to organize a custom AMI via a convoluted AWS-specific process, please advise.

It seems that the market for "use our virtualization as if it were bare metal" is quite small. I am very interested in expanding this list to as any providers as possible.