SOE and Reliable, trustworthy, legit companies only
Pick one if your allowing SEO you can not be legit, could be reliable until/if arin actually enforce there regs and if they have lied in contracts before can you realy call them trustworthy. Might want to make sure they have legacy IP's.
You can contact any Hosting company and ask them if they are fine by providing 20 C Class IP's on Dedicated server. Hosting provider might ask a justification for those IP's and you might need to provide him the domain names which will assigned to those C Class IP's.