@@BeginAgainDay, I use the unjury unflavored powder and I either order it online or I get it from my NUT or (sometimes) I can find it at a local vitaminshoppe. Recently though, I have switched to using collagen and Gelatin instead - higher Protein, better for me, and better flavor. These are the ones I use most here and here. The collagen won't thicken, the gelatin will, and that's half the fun.
Do let me know if there's anything you want that you haven't seen on the blog and/or can't imagine could be bari-friendly. Or if there's something you want more like it or else that really didn't float your boat, the more feedback the better.
Also, congratulations on your upcoming sleeve. Try things before surgery, but if there's something on there that tastes 'off,' do consider trying it again post-op, our tastes change in the strangest ways.