Many people who use the teensy are likely to be noob solderers. This would include me if I tried to make a custom build. A microcontroller is 20 quid, so I would be pretty scared of splattering hot solder onto it. So why not have a protector, for a couple of pounds or dollars or whatever, it would snap onto the pins in a similar way to an arduino shield and provide it's own pins to solder onto, so if you screw up you just pull it off and pop on a new one. I'm not sure what the construction of this device would be but I'd like to hear your views.