That would defeat the purpose of the system. Just the existence of a backdoor makes the system vulnerable and devoid of purpose - anyone, with sufficient determination, can exploit it. Besides, anything even close to such action would utterly destroy Tor and spark another service that could be even more dangerous in wrong hands.
I know I shouldn't feed the flamebait, but... These things you talk about aren't open and certainly aren't in the spirit of Open-Source. You should provide choice and make it a well known alternative, but forcing them to use something? Are we any better then? If Open-Source supporters start doing these things, then I think the cause is lost.