While i myself have access to letter heads, but I am meant to use them for my official purpose. For this purpose, only HR department should ideally use letter heads. While my boss is okay with putting it on a simple piece of paper with his signature and stamp, he is not comfortable giving it on a letter head since he is not supposed to. I though email might be better since the email address would show that it actually came from the official email id. What if I support it from some of my colleagues? And also take a print out of the email on white sheet and get it stamped and signed by the boss?