I have not been able to find out if OmniGroup is creating anything but I know David Allen Co. has teamed up with another company to develop something.
I just might go back to my iPhone!
I am also in the same boat. Macbook Air, iPad and Galaxy Note 2. I contacted Ken Case at Omni to see if there is any chance (any at all!!) of Omnifocus being transported to Android... Nope! It was a good response that they are sticking to what they know and don't want to dilute the product. (dilute is my word, can't remember theirs exactly)
I really prefer the Android OS generally and now use Any.DO but not as well as OF and it is not OF by any stretch...