I don't think Hyperion will release OS4 for the SAM460 until the X1000 is released, or at least is a lot closer to being released than it is now. Why risk losing sales on a high dollar system to people who would be just as happy with the 460?
Don't know if this is true, but in my own case if the Sam460 is available soon and the X1000 is available at some far-off, unknown date, I know I will buy a Sam460 sooner. Later, if I get an X1000, I would either keep the Sam460 or sell it (or my Sam440, or both) to help raise money for the Aeon machine.
However, if both machines hit the market near the same time, I will choose one or the other. Maybe I would decide the Sam460 is good enough for me and not make the big X1000 investment. Or maybe decide I just have to have the biggest, baddest, fastest AOS4 machine ever and put all my resources into an X1000 purchase.
Meanwhile, I am enjoying my Sam440 machine quite a bit so am at a place where I can be patient as I ponder my next foolish outlay in cash for this hobby.