No, I can't give you a specific time. Finishing the game is too far away for me to even make a rough estimate. I'm making steady progress, but the list of planned content seems endless. :D
I have some notes for other things I could do after Renryuu, but no detailed plans yet. And even after the main story is done, I'll probably keep adding content to Renryuu for a while, before I'll even consider to start something new.