I treat SKS fenders as stock material and always keep few redundant ones lying around, both new and broken pieces + stays, brackets etc. I glue them together with epoxy (slow-setting, urethane also OK) to any length I want (read 180 deg coverage or more). The front of the front one can be suspended under the rack with a bracket normally used for suspending a fender from the seatstay bridge. Such a bracket is preferable to another L-bracket because it is easier to dismount and mount the fender.