Hi Scott and George
First of all, let me say that I agree that George Kaye is the leading expert on all the arrangers that we discuss in this forum. It is fine with me if he has the last word. But George, others like to help too. I hope you are not suggesting that the rest of us should not bother to share what we think or know. But I do want to hear more from you. I would like to hear more about the Korg I40m. Also, if you know what this Kurzweil Arranger is about.
Scott, to try to answer your last question, I do own the QY70. I waited through the QY10, QY20, QY22 until Yamaha got it right with the QY70. I have a Roland A50 keyboard, 76 keys, polyphonic aftertouch, that I like and did not want to give it up. The QY70 does turn the A50 into an Arranger. To answer your last question, I tried inversions yesterday and got patterns only in root position. Hopefully, George Kaye can confirm/disconfirm this.
To answer your previous question to me, I consider the QY70 to be a marvel. It seems to have no competition in its size range. Still, I hesitate to recommend it too strongly to you. I found the QY70 tedious to use and purchase a PSR-8000, which I find much more fun to use. When you want to change from pattern 20 to pattern 80, do you really want to step through 60 patterns? Do you want to have to hook up to a computer to enter or save data to a disk.
I recommend thinking carefully about the need for a battery powered device. Consider the Korg 140m, the QY700, and there is a general music arranger module. It sounds like George Kaye would recommend the i40m. All of these devices have disk drives so that you can easily play midi files, load and save styles, etc. If you cannot live with the extra weight and requirement for AC power, the QY70 is your best bet. You might love it--or you might be irritated by its compromises.
I hope this helps.