Access WeDo on OS X from a real programming language
It is possible to drive the WeDo from Python on a Mac, without a kext.  I've only tested motors since I don't (yet) have the other sensors.  You need to access the USB HID device directly.  There are a couple of prerequisites to install:


cython-hidapi, which itself depends on 
hidapi; homebrew can install that for you.  
cython likewise


You'll likely want XCode and friends installed to be on the safe side.

There are a number of forks of cython-hidapi available so your mileage may vary depending on which version you use. I don't remember installation being problematic.

Once those are installed and your WeDo is plugged in you can do something, at a minimum, like:

import hid
import time

# vendor id, product id: 
dev = hid.device(1684, 3)

# turn both motors on
# HID format is reportID, message type, data1, data2, ...
dev.write([0x0, 0x40, 127, 127, 0x0, 0x0, 0x0, 0x0, 0x0])

time.sleep(1)

# turn them both off
dev.write([0x0, 0x40, 0, 0, 0x0, 0x0, 0x0, 0x0, 0x0])


The changes to get WeDoMore to use hidapi instead of generic usb on a Mac don't look to be too onerous.  If I manage to get something committed I'll update my answer with a link.

[Edit: I've committed a fork of WeDoMore that adds support for motors on the Mac here.  Again, I'll update if the pull request gets accepted]

Small side-note: The WeDo can also drive 9v motors with the correct converter cable.  I think it's possible to read the RCX sensors as well, but mild soldering may be required (see, e.g. here for a proof of concept).  But if the WeDo can be fooled into reading the devices then Python can be used with those other sensors.