I got some 220 Agfa Optima 400 in a bulk film buy, obviously outdated but claimed to have been frozen, and bought a 220 insert for my Mamiya just to shoot it. The 220 insert for the 645 Pro and Pro-TL backs works fine with a 120 back so investment was $12. The Optima 400 is fine, so I'm glad I got it, and it's worth having in case I come across other film, but as far as I know only the Kodak is available new and the thing about that is that a 220 roll costs more than twice as much as a 120 so it's not a savings of anything but reload time. I can't see myself paying more for it, and 30 exposures rather than 15 is more often a liabilty than an asset for me, though I could see some situations where it wouldn't be. An existing light event outdoors at night with a few 220 loads of Delta 3200 and the 80mm 1.9....ah, dream on!
But I wouldn't hope for more film to be available in 220.