Hmm...the Limited edition Lost Archives, sold out much quicker than the 10th memorial, it's also the one I ordered, however I don't know when they have dispatched it, i just know i ordered mine last saturday, they took the money and thats it really, i have no idea when it will arrive. also;
"There is only 54 of Guilty Gear XX Accent Core Plus : Collectors Edition - 10th Memorial Book in stock "
edit: zavvi has changed their product page for the limited edition version, it is now £24.85 and confirms to have a metal keyring, most likely the ones with these sets, i don't know if its a normal game with the key ring added or if it has unique sealed packaging, however i am not sure if these are limited or not, i would prefer to see an actual picture of one before i buy, here is the link again (for the wii, psp is the same price)...
http://www.zavvi.com/games/platforms.../10457859.html