At this moment the Dev Portal Activation error page (see the attached screenshot) is not listed in the CMS content for customization. A customer is requesting a feature enhancement that will allow this page to be customizable it look and feel. Is it feasible?

The mentioned page is:

https://<account>.3scale.net/activate/<activation_code>

This activation error page appears when the signed up user clicks in the activation URL received by emails and the token is already expired or the account is already activated.