Steve Chamberlin at Big Mess’o Wires has successfully added Smartport compatibility to his Floppy Emu product. With the latest update, it now can read and write to most of the common disk image formats used to emulate 5.25, 3.5 and larger drives.
Compatible with the Apple IIGS and Apple //c, IIc Plus, the Floppy Emu is $89 USD plus shipping, and has additional options available (extension cable, case).