I was recently contacted by Jesse Fox of Seneca Cycle Works and we schemed up a saddlebag modeled on the Carradice Nelson. Part of the fun of a custom bag is that you get to make it become a part of the overall bike scheme, and Jesse's bike is red with black accents, so we went with colors that mimicked the bike, but didn't try to compete for attention. We also dispensed with buckles on the pockets since they can be fiddly to open (and close) when you just want to get into them. I also tried to flatten out the wooden support spar on the inside since I find the dowels to be intrusive when you are trying to overfill the bag, although I'm not sure my solution made a significant difference.
As we all know, the downside of large saddlebags is the dreaded thigh-rub, where the bag entends perpendicular to the bicyle behind the saddle and can hit the back of one's thighs when pedalling. To solve this, Jesse and I planned the bag so that it would mount on a custom rack that would both support the bag but also hold it out from the seatpost a few inches. Jesse's progress photos of the rack remind me of a randonneuring front rack turned around, which sort of makes sense when I think about a big saddlebag basically being a tilted box hanging from the saddle.
Rather than try to coordinate sizing and placement we decided I would just finish the bag based on a quick sketch and then Jesse would build the rack to fit the connection points I'd worked into the bag. A strap will run through the leather wear patch to fix the bag from below.
I love projects like this and am grateful to Jesse for his interest in working with me! I hope we get to do it again.
(Middle and bottom photos: courtesy of Jesse Fox)