The Kelly was originally designed as a saddle-carrier. So, in terms of construction, it can hold a fair bit. The minimized version of the saddle carrier that we know nowadays as the Kelly still has the construction. I do agree with you though in that I would be uncomfortable with a 35 or 40 Kelly as I would feel that I cannot put 'bricks' into it. However: these bags are very, very, very durable and hardy, so if you're looking for a purse, they will be great and hold a ton of stuff that ladies like to carry around. If you are looking for a tote to shlep the Encyclopaedia Britannica in, then the Birkin might be the better choice IMO.