Of course jailbreaking A5 devices are possible but there are something more to do to make it public. Learning from what pod2g has said on his blog, jailbreaking iPhone 4S or iPad 2 is possible but require developer account which is the reason why they can distribute the tool.
That is why we have seen jailbroked A5 devices on YouTube but not the tool to download. Here is what pod2g posted on his blog:
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.
Learning from this, we can conclude that pod2g might have something in their mind already and hope that they can find solution soon and get the tool publicized next week as promised.