This is a long-held desideratum by anyone who has had the fortune to read, study, teach Ørberg's Lingua Latina, Pars I Familia Romana & II Roma Aeterna, and has also had any interest in the direct teaching of ancient Greek. Some time ago I embarked on a straight translation of LL chapter 1 into Greek, and it's floating around the web.
Now I find myself teaching some Greek, and have returned to the project of translating the course. I've just today finished translating and adapting chapter 2. In one sense doing a straight translation is very 'easy', much easier than composing a comparable course from scratch. On the other hand it is fraught with difficulties, with differing grammar even in the first 2 chapters, not least the problem of nouns, and declensions, for very basic words.
My hope is that I might secure some copyright permissions to produce the translation and make it public. Given that the main interest in such a text is its pedagogical value rather than the intrinsic storyline, and I have no plan for financial gain, I am hopeful I might secure such permissions, so that the work will be freely available for others to utilise (with all the faults I am making!).
Update (4/17): Almost finished on chapter 3.