I'm in the market myself and I'm seriously considering the Beckett Siminon Gaston bag, unfortunately I missed their 30% off Christmas sale so going to wait for a sale to come around again. I cant speak for their long term durability as I haven't owned one yet but I do have some of their shoes and the leather and fit and finish of their shoes is amazing. Also primarily a shoe company not a bag company so options are limited.

They are a made to order company though to keep inventory costs down and pass savings to the customer so you may have to wait for whatever you buy from them.