It seems Miche have 'sprocket boards' (as they used to be known)for cassettes- In other words it's possible to get individual miche sprockets for Campag or Shimano freehubs. I guess they won't have HG 'capability' for swift shifting, but that may not be an issue.
I'd certainly like 7 speed cassettes in close ration to be available. 14-20 would do me nicely with my triple on the front. the closest I have are a stock of 13-21 to last me out (need good chains also of course!) There may be many more of us that want 7 speed close ratio? But of course large companies (like Shimano) say "nobody wants them - look we've made no sales" Well........ If you don't have them for sale, that's hardly surprising!