FWIW, it is very easy to convert the 9900 to use MC cartridges. All you have to do is change the phono preamp gain (change 2 resistors) and change the input impedance (2 resistors.) I did this with my Rotel RA-1412 integrated amp. I haven't had to do this with my 9900 because I'm using it with a Luxman PD370 TT and a Grace F-9 cartridge, which is MM.
The 11000 is very similar in design and construction to the 9900. They share the same service manual. The 11000 has more power, that's about it.
I will say that I don't much care for the AU-D11-11. It sounds wonderful when it's working, but because each stage is DC coupled, each stage has a DC offset pot to adjust for each channel. If the pots get dirty, you get a high DC offset at the output and the amp shuts down. Also the balanced amp design is a PITA to adjust, with no sonic gain to offset the complexity and tweakiness, IMO. The way the case is constructed, it is necessary to remove the plastic sides to work on the board behind the front panel, and then the transformer flops around unsupported.
The AU-X1, now there's a fantastic amp! Some of them have oscillation problems, easily fixed.