Does any other provider (Mailgun? SendGrid?) support EU standard clauses and send them on request? Mandrill does this. EU startups are out of options otherwise.
Additionally, the landscape will change on this once Privacy Shield, the successor to Safe Harbor, is enacted. It will offer stronger protections and guarantees to EU customers without the need to have model clauses signed between entities.
Our sales team sales [at] mailgun [dot] com can talk to you about your specific situation.
Your sales team did not answer to several inquiries last autumn so some of my clients switched from Mailgun to Mandrill last autumn.
The model clause process is not trivial and often requires work between the legal teams from Mailgun and the respective EU company. We've gone through the process and can definitely help any of our existing or prospective customers get through it, though. Every business is a little different, so we'd need to talk through the specifics.
My email's in my profile - let me know if you need the details.