SMPs are asking for the same letters you need for med school admissions. SMP applicants are, in general,
almost ready to apply to med school, and LORs are just one item on the list of things you have to have in place when you apply to med school. Furthermore, I wouldn't plan on getting more than one good letter out of an SMP - you need 2-3 more from undergrad or elsewhere.
If you're eligible for an SMP, you've taken a year each of genchem, ochem, bio and physics - all science. Plus you've taken some math, which you can use for a science letter as well. Any possibilities from those profs?
I suggest that you search SDN for "LOR" and see what suggestions folks have for finding letter writers in a pinch. There are sticky threads at the top of pre-allo and pre-osteo.
What I'd do:
1. Write my med school admissions personal essay. Get enough comments from reviewers (NOT from my peers: reviewers are educators and other professionals) to produce a good draft.
2. Write letters to 5-6 professors in whose classes I got A's. Remind them that I did well in their class, and that I enjoyed it and remember it well (such as <anecdote>). Tell them I'm now pursuing medical school and am in need of their support. Would they be willing to sit down for a bit of a chat, so that I can refresh their memory of me, and discuss my ambitions? Enclosed please find my statement of purpose in pursing medicine and a picture of me.
3. Courteously, relentlessly, consistently communicate with any fish that bite until the letters I need are at Interfolio et al.
Best of luck to you.
