The exploit I used to inject the untethering files to the 4S relies on having a developer account, and can't be released publicly.
It's the same reason why @MuscleNerd has an iPad 2 tethered jailbreak but couldn't distribute it.
So, we need to find a distributable exploit to remount the system partition read/write and to set Corona files at the correct places.
Why A4 version of Corona was easier to release?
Because a tethered jailbreak is a good way to install Corona!
Why don't you do a tethered jailbreak then?
A tethered jailbreak also relies on an exploitable vulnerability that we still haven't found yet!
pod2g, release this stuff quick,