Yes they are available now. Audi is funding the 20% off MSRP. All of these fixed TDIs will get a 10 year or 120000 mile warranty on emissions related components and the engine long black assembly. We just bought a fixed 2015 Q7 to replace our 2011 that is being bought back. The performance of the fixed TDI seems fine. Very little difference. I hardly notice. IMHO the 20% off is not enough though. If you needed to sell it in a year it would be a 4 year old low mileage vehicle. If you keep it 5 or more years and drive it lots of miles it makes sense.
We bought a fixed used one with 38000 miles but new brakes and tires. Price was nearly 40% off MSRP.

I expect it WILL use more. Some reports say 40% more. Our 2011 would use about 5 gal in 10,000 miles. I did my own services and DEF refills. If it doubles and I have to fill it in between at 5000 miles, I can live with that. An extra $20. in DEF every 10000 miles ( total of $40.) isn’t a big deal to me. VW Audi should have built them this way and provided a DEF fill hose with each vehicle. Might have discouraged a few buyers but they could have avoided this massively expensive settlement. Not as much trouble as plugging in a Tesla for hours every 300 miles in my opinion.
I will report when the AdBlue needed message comes on. Only 2000 miles in so far.

Our 2011 Q7 averaged 24 mpg over long term use. Thus just over 400 gal of diesel fuel in 10000 miles. In that same 10000 miles it would use 5 gal of DEF. Thus DEF consumption was about 1.25%. As mentioned before, if it nearly doubles and requires addition of 5 gal every 5000 miles, I won’t find this to be objectionable. I would still choose diesel over gasoline for its performance and overall efficiency. What is perplexing is why didn’t VW Audi realize that we would buy them anyway? The lie is so much more damaging than a bit more frequent DEF additions would have been.