Well, they have to find the weaknesses of iOS 6... If it has the A6 it could take a while. It could be weeks or months...I believe...
I took quite a few months for the a5 and ios5 and we already burned the exploit so Im thinking 4-6 months
They don't release tethered jailbreaks. They work at it until it's untethered, then release it. If it's tethered most people wont do it. They will only release a tethered jailbreak if they find a bootrom exploit (unlikely).
I am not talking about releasing it, but I think/hope the devs might have some userland JB they can use.