It would be the same technology as any other repeater. They're illegal on 11M, but I would be surprised if there is no one doing it. There are 10M repeaters, so a lot of the "export" radios have the capability. The $130 Stryker SR-94hpc, as an affordable example.Anybody have a 27 mhz repeater??? Or the information on building one???
I would/did use uhf, though. Cheaper and easier, much smaller antennas, and there is a way to do it legally.