Hi Mike,
I have setup a virtual machine running Ubuntu 12.04 to test out MTP and have found out that it is quite annoying to deal with. mtpfs does not work out-of-the-box. A Google-employee has made go-mtpfs, which supposedly works better, but I have yet to experiment with it. With normal mtpfs it seems that you need to setup udev rules for your specific device, meaning that it can't be used as a catch-all solution for MTP devices. I will try to experiment with go-mtpfs and see if it can work as a general solution without having to do specific udev rules for all devices.
As a side-note, on my Ubuntu 13.04 desktop, MTP is handled by an updated gvfs and is accessible in Nautilus, but does not get mounted as a part of the filesystem in a way that is available outside Nautilus. Which is why I haven't actually played with mtpfs before, despite having an MTP device :)