I think that a thank you note is a great idea (esp if you think that you will need to borrow again) but I would not mention that it is paid because it implies that your boss does not check his records. I think that the note written in the past tense. "You really helped us out and we appreciated it greatly blah blah blah," will show that tit is paid. Anyway, what is your next step?
That what is paid? ;-) lol I had to. I'm a 6 year old, I swear.
I saw that too. lol I think I'll include that in my note...
Thank you for the loan blah, blah, blah. That tit is paid, fool!
ETA: 'Cause, you know, "fool" is still what the cool people say.