This is definitely on my todo list, I just have to figure out the best way to handle it. Ive been looking at the 0xBitcoin contract and considering moving FRK to it. But, it might just be better to create an online FRK wallet and from there letting people move between the chains that way. I just don't know.
Maybe you could adapt what Bryce did with the Tao "exodus" site which lets people move from the old Bitcoin-forked version of Tao to the newer EVM chain:
https://exodus.tao.network/signup/I helped beta test it a few months ago and it works well.