Thank you for your question/request. I have added this to the backlog. No guarantees, but I will attempt to generate a profile for a release in the not-too-distant future. Stay tuned.
As an alternative, it is possible that there is a user-generated profile available via the Adobe Lens Profile Downloader. You can download the application from the following page.
There were no profiles for the 800mm lens. Indeed many of the downloads appeared to be for quite old-perhaps even non-AF-lenses. So, I guess my only option is to wait.
I'm following up to let you know the profile will be available in the next release of ACR. I'm not able to specify exactly when that will be, but it should be sometime in the early spring timeframe.
Thanks for your patience.
Thank you for the update.