I don't think there will be a Mark IX anytime soon, or if there is, it'll be a Mark nameplate thrown on a car not worthy of the Mark name. Look what Lincoln's done already- put the Mark name on a truck, of all things, then made all their cars now MK this or MK that, which, to me, kind of alludes to the Mark name. I'll be honest, I don't even like the new Lincolns anymore, when it comes to comparing them to what they used to be. They compete with Buicks now more than they do with Cadillacs. Lincoln needs to get its name back in good standing before anyone is going to take it seriously in the luxury car market so it can successfully build a Mark IX, OR it needs the Mark IX to bring it back into good standing. If they could build a luxury sport coupe on the same level as the CTS-V coupe, it would bring a spotlight back on the brand itself so they could up their game all across the board, possibly to what Lincoln USED to be. It would be like what the Mark II did for Lincoln back in the 50's.
Anyway, that's just talk. Ford/Lincoln isn't in the position to do anything like this now. One thing I think that messed Ford up and got Lincoln off track is up until a couple years ago, Ford owned too many luxury car brands, and I think maybe they decided to hold Lincoln back a little to keep them from competing in price with some of their lower-priced Jaguars and others. Given their current situation, I think they should've kept Mercury to compete in the Buick segment and worked on elevating Lincoln back up into the Cadillac range, but of course, that's not the way things worked out.