Swift Industries also carries them here:
https://builtbyswift.com/shop/swift-campout-pockettender/ Made by the awesome Randi Jo Fabrications in Elkton, Oregon. I read that Rivendell's bags were custom designed slightly larger than the normal ones. Randi Jo doesn't normally offer the Pocket Tender version of the Bartender bag, but occasionally do custom runs fro Swift, Tarik Salah, others I've seen. I have two, one with pocket and one without. I prefer the pocket version where I keep my Snowpeak spork and round flask on the outside along with Paul brake tool/bottle opener. I've found for longer rides I pretty much can't live without it.
Contact Randi Jo if you want a custom one with pocket made. She's even offered to sew my own supplied patch on the pocket if I ship it to her.