OVH should call it OVH Linux, similar to Amazon's AMI (not Ubuntu based). With no association to the Ubuntu trademark they should be spared with the need to recompile from sources.
Ubuntu trademarks would still remain in package names, changelogs etc., so a full recompilation is still required
This makes it sound easier than it really is. It's not just recompilation, it's patching everything to remove the trademark. Then you have tens (hundreds?) of custom packages to build and most of all to test and maintain.