This is a simple model for a MagSafe mount, for use with iPhones (and potentially other devices). It's not really much use by itself, but may be a handy starting point for embedding a MagSafe mount in another print. The pictures show this model used as part of an iPhone mount I made.

It has slots for 8 10x5mm rectangular magnets, at thicknesses of either 1 or 2mm. They press fit quite firmly, depending on your printer tolerances, but I'd strongly recommend using a drop of superglue to keep the magnets attached. You'll need to experiment to figure out the ideal magnet orientation.

1mm magnets are enough to hold my phone, but your mileage may vary, so use at your own risk!