Gaver has 6 foot blue spruce left, according to their website:
https://gaverfarm.com/
You waited too long, OP! This happened to us last year and we ended up with a decidedly Charlie Brown-ish tree. This year we went Thanksgiving morning even though it felt so weird, and I’m glad we did. The farm (we go to Pine Valley in Sykesville), was packed with people who had the same idea we did. I kept an eye on their website out of curiosity, and they sold out middle of last week.