Hi Dan:

Your idea is a good one for certain special applications and has been done several times. B&C used to advertise one in S&T many years ago. Thier's include a schmidt corrector and grating for a fast photographic spectrometer. Since the Flat would be a lot more valuable and many times more difficult to make it would seem me to be a waste of money and manpower to make a scope and apply it to typical use.

No it could not be a Dobsonian because Dobsonian is a philosopy and not a telescope. Such an extravagant exercise would be anathemia to John's practical junkyard scope making.

Have you though where the eyepiece is going to be at different parts of the sky? One will either end up with and extremely cumbersom mount or need to stand on their head to view. I don't want to discourage you but as you asked for input, I am providing some. I estimate that at the bare minimum this scope will not only be extremly awkward if of any good size and cost four to five times as much to make with litte or no performance advantage. If you want to try a two mirror system you might go to the Stellafane site and link to unusal scopes.

Good Luck and Let us hear, -Rick