Tiny Core already runs on many Allwinner A10 systems, including Mele (with SATA), MK802, Marsboard, Hackberry, and Cubieboard. So if Lime is a typical uboot A10 system it should not be much of an effort.
Of course without actual hardware to test the actual effort is unknown. A10 maybe popular but it requires several "compiled" configuration files that other arm systems do not. Additionally there does not seem to be a big demand for these Allwinner arm systems, especially single core.