What about a current employer that you've only been working at for a few months (it's a part time position and I'm not ready to inform them I'm leaving, and requesting this letter will surely raise some questions from them)?
Also, for the Employer Reference letters, the 2 main jobs I've held over the past 10 years were at small Canadian non-profits (I was a temporary resident at the time), but neither of my supervisors is at the organization, and because they're so small, no one currently there has any experience with me, and I'm not sure what there is on record other than my T4s?