The whole PSJailreak/PSGroove thing has a worldwide shortage of the all the compatible AT90USB chips.
While I wait for my order (which at the moment seems like it could take up to 2 weeks -.-) I will be looking at the PIC 18F2550 Port of the PSGroove software and trying to design a dongle for that.
The nice thing is that the 18F2550 can also be programmed with a USB Bootloader, this means that it would also be fully upgradeable via USB, with no extra hardware!
with the possibilities the exploit opens for sure a lot of people will remain on 3.41 - this is way more worthwile than the 'announced' OOFW3.21 months ago.
UPDATE: It seems that due to funding and parts shortages it will be almost impossible for me to continue developing this project myself.
So I have decided to just upload the board design. I'm sure a lot of improvements could still be made to it.
Note: The USB connector is supposed to be a male type A connector, since there is no such part available for eagle, I used a female type A socket, keep that in mind when using this design.
I will still be active in these forums if anyone needs help or has a question.