You must still have a copy of each IOS you installed on your SD card right? If you had a failed IOS60 install it would brick.
Honestly I don't think there's much of a solution.
I'm assuming no preloader as you'd have mentioned it.
Bluetooth module OK.
You could possibly get an infectus chip, solder it on and copy another NAND across. Your Wii shouild be boot1 vunerable. Erikie has experience of this procedure so you might like to ask about it.
Whether it's worth the cost though when a Nintendo repair/refurb might be cheaper.
Not really doing much Wii stuff these days.