It appears that my application was thrown out by UC-Boulder without being evaluated. I suspect that this is because one of my letters arrived late, but my application was submitted well before the deadline. I emailed the graduate director (who was very nice) asking what happened, and she basically said that my application was probably tossed.
I thought I was a very good fit for Boulder, and my results so far show that I am competitive at equally-ranked (and better) schools, so this stings a bit harder than a simple rejection. Really unsure how I feel about this. Oh well.