Ilford is taking orders for its annual "ULF" production, that includes 70mm unperforated.
http://www.ilfordphoto.com/products/page.asp?n=137
Good advice on that bnphoto site.
Just adapting to 120 spools will leave the long edges of the film unsupported across the film chamber; if you choose to go that route, be sure to advance the film just before taking each picture to minimize slack.