I feel the day is coming that hub motors will be given splined cassette fitment hubs which may open up more opportunities to fine tune rear cogs and gears. There is one motor I can think of like this but I have no idea how it has been tried and tested and it is not a magic pe.
There are actually two hubs like this I can think of.
The Crystalyte G-Series and the 8Fun (Bafang) CST
Crystalyte G-Series
8Fun (Bafang) CST
I have asked around a lot about the CST and it isn't very well tested. Those who have tested it say it works good, but also that you need to buy the 500w version which can be hard to source (To be precise: one person said that after testing both 350 and 500w versions). This is a geared motor very similar to the MAC or BMC only with nylon gears and lower power. It also comes very low geared so it doesn't go fast, but it has plenty of torque.
I believe the G-series Crystalyte is more similar to the MagicPie (as in direct drive), but at a smaller size it probably can't compete with the torque and willingness to over power that the MagicPie has.
Have you tried fitting the DNP epoch to the MagicPie. I tried it but it wouldn't fit right like the Shimamo did. I tried the 7 speed freewheel, might be that the 6 speed will fit better. I also tried the DNP on a MAC motor without success, but I know it would fit if I had the right spacer.