I noticed that private beta accounts are shown on FlairTM but not on the accounts tab or reputation graph of your SE user page.
This explains why private beta accounts are shown on FlairTM but not on the accounts tab of your SE user page. The reason given for this is a good one:
However when it comes to flair, we show it off, as much reputation as you have everywhere all added up, because showing it causes no harm or navigational confusion.
But I think this argument isn't sound when it comes to the reputation graph: the reputation graph is showing off as much as is FlairTM.
In the private beta case, anyone not in the private beta couldn't use the link to go to your profile there...so showing it on the Accounts tab doesn't really make sense.
Also this isn't a sound argument when it comes to the reputation graph, since that doesn't include links to the accounts.
So, how about showing private beta accounts in the reputation graph?