I hope not! I really don't want to pay extra for touchscreen feature etc. That is not the purpose of iMac. iMac is a desktop computer and anyone who works long hours on computer has an ergonomic setup so moving things in and out is not ideal. Either Apple introduces bigger iPad or they will create a new category and introduce Apple Studio (what MS studio is) and design that product specifically for those artists that want to use it like that.
People argue against touchscreen are the ones that understand why it is a bad idea.
If Apple makes a touchscreen then it will be flat device or device that you put flat/low angle. No other way works and those who say otherwise simply have no clue about ergonomics.
I hope Apple is smart enough to know not to blend those two products together and create a 'meh' compromise.