Thank you for your patience. We have released custom domains for Azure AD B2C to public preview.
Documentation can be found here: https://docs.microsoft.com/en-us/azure/active-directory-b2c/custom-domain?pivots=b2c-custom-policy
This is in progress for Azure CDN from Microsoft.
-Max G [MSFT]
Thanks for the feedback. We have this in our backlog and needs to be prioritized with other features. for those who would like to see this sooner, please vote for it.
Thanks for the valid suggestion. Your feedback is now open for the user community to upvote which allows us to effectively prioritize your request against our existing feature backlog and also gives us insight into the potential impact of implementing the suggested feature.
An error occurred while saving the commentFabian Flanhardt commented
Looks like it was a little late when I posted the example. Here is a more accurate one: ;-)