Is federal certification of voting machines that can handle ranked-voting an insurmountable challenge?
No. Federal certification is voluntary under federal law. There are no federal rules applying to local elections and that federal voting machine guidelines even for state elections are voluntary, although many states have piggy-backed onto these guidelines. As of 2008 there was a substantial bottleneck for getting systems tested by the federally certified independent labs, though this can be expected to ease over time.
