The line is called Sackville and they look really promising! Hopefully, Riv can keep enough of them in stock. Here are some pictures of the LARGE bag from the Riv site.
This LARGE Saddesack (about 1,425 cubic inches without overstuffing, and it is quite overstuffable) is the most capacious, easiest-to-load/unload saddlebag we've ever offered. It's big enough to require a rack or some kind of under-support, but it holds a massive heap of anything. Ideal for camping, commuting, shopping. Combined with a bag or basket up front, it's great for ultralight week-long tours.
On the country side, you can force in a tent, sleeping bag, clothing, toiletries, and small stove and kitchen.
On the ciity side, a laptop, books and files up the wazoo, and shoes and clothing loosely packed.
On the shopping side, stacks of binders, and armfuls of cauliflower, or a Thanksgiving dinner for four, turkey included. (One of the photos shows what Jay here recently picked up on a shopping run for lunch and snacks here.)
Yet it's light, and never in the way even empty.
The Sackville isn't just another fancy dupe of a Carradice either! They've added some pretty neat additions. Most notably are zippered pockets that face toward the rider that you can access while riding. Pretty cool! A great place to leave some Sweetarts or phone.
They also feature a small zippered pouch that can be separated from the main bag. So you can store your valuables in it while on tour and take it with you.
Alongside the LARGE version, they're coming out with a medium-sized bag that can be used without a rack (if you have enough seatpost showing). The medium-sized bag lacks the front-facing zipper pockets (bummer), but has the removable zippered pouch.
Which would I get? Hard to say, but I'd lean towards the large one to quench any existential doubt like "geez, if I only got the other one I could carry more stuff for this trip, etc.," They're taking orders now and the bags themselves should be in mid-March.