LOL. Not to gross you out, but when son was in the mountains for winter-survival, they had to cook a rabbit to eat. He said he had been starving so much that even at the cheeks out of the thing, and they were GOOD. I don't know about beef cheek. I've never seen any for sale. I'd try it for the boys if I did.
Try Walmart, if you shop there. They have a small selection of "variety meats," things like beef cheek, tongue, tripe (not the kind dogs eat), ox tails, and other odd bits, occasionally even heart (I'll be jumping on that if I see it again.) It will probably be at the end of the case where they keep the other beef. The cheeks I got were in a vacuum pack, and labeled in Spanish. In the package, they look just like any other really dark red beef. I know lots of people don't like Walmart, and I honestly don't care for them much, either, but you can sometimes find some interesting things there. Around Christmas, our local store had pig heads in the freezer case! No joke - whole pig heads. I know people use them for various things, but I certainly didn't expect to see them there.
I'm not easily grossed out. Actually, one of the things I have not had to struggle with that I think bothered a lot of other members starting out is the idea of handling raw meat, including strange animal parts. It just doesn't bother me, and never has. I didn't grow up in a family of hunters (I wish now that I had), but my father and I often fished when I was a child (Mom mostly watched), and one of the rules was that I had to bait my own hook, take my own fish off the hook, and at least help him out when he gutted and skinned or scaled and filleted our catch. I think that experience early in life may have stuck with me, in terms of what makes me squeamish.