Target has some nice plaid shirts right now, including ones that aren't flannel. Also Old Navy, especially online where they've got more colors than in store. Let me see if I can find some links.
Find 1 is from BR, and I bought it earlier this fall - it's not flannel, just a softer cotton. Nice in-between weight imo. 2 is the same cut, I believe, in a white/blue; might be lighter coloring than you want.
ON: 3 is popover style like one of the ones you pinned from Loft; 4 is full button-front. 5 & 6 some more darker color options.
Gap: 7 is actually a plaid chambray, kinda cool. 8 - buffalo plaid. 9 - a smaller check.
Target: 10-13. I remember some more colors than these in store.