It's interesting, I checked the a Google link you provided and it seems others are having the same problem with the mini retina.
Yes I have tried resetting both devices and turnin airdrop off and on. It is set to "everyone" so it should not be a contacts limitation.
The last time I tried it I could not get the mini recognized by the sending IPAD Air, but when I turned on my iPhone 5s, it immediately came up on the IPAD and I was able to transfer the picture. The mini never came up at all and I had to give up.
I have had no luck either sending or receiving from the mini.
Maybe I have to wait for the next ios7 drop and hope it's a bug that gets fixed. I am now out of ideas....
Jim Klinck