Thought I'd update the current state of large aperture Maksutov scopes.
Russian scopes are not being fabricated for commercial/amateur purchase. These are only available second hand.
The Intes 815 that Wavy mentioned earlier is now in New Zealand.
There is one manufacturer left that produces large aperture Maksutov optics,
Ottiche Zen, but this is the optics only, not the completed OTA, from 145mm through to 300mm aperture. Ottiche produces some really outstanding quality optics too. Ottiche's Maks are all Gregorian Maks, that is the design that has the silvered spot on the corrector plate like the Skywatcher Maks have. Ottiche also manufactures Schmidt Cassegrain optics.
Astro Physics is making some large aperture Maks, but these are only to fulfill orders made years ago! No new orders are being accepted, so the only way to get you hands on one of these is to buy one from someone who's got sick of waiting for their's.
~x.X.x~
If you have a 7" Mak or larger in diameter, please still let me know. There are a few of the Meade Maks out there, but damn they are hard to track down now. To date, I have not seen one, nor heard of someone who has one or knows of one. These are harder to track down than an Intes or Questar 7!
Alex.