Writing to the account object in SFDC?

Being that ABM is an account-centric approach, it is becoming increasingly necessary to update some data fields on the Account object to track efforts, trigger processes, orchestrate activities, etc.

I understand by default Marketo makes Account object read-only for Marketo — I understand why. But it would be so nice to be able to designate a few SFDC custom fields on the Account object to be read/write for Marketo sync user.

Anyone know any magical tricks to achieve this?