There is another image floating around of Harlequins, which reveals a look at the new Starweaver model, perhaps the best we have seen yet. It definitely looks like a small lightweight and fast Venom variant. The image above is a Venom, and there are some similarities with this to compare.
Follow the link and see for yourself.
via Tiller5 on Warseer
http://www.warseer.com/forums/showthread.php?403593-A-Laugh-For-Christmas/page50
Just picked up my pre orders from my local shop, and saw this nice bit of artwork on the instruction booklet. Forgive if I'm wrong, as I'm not much of an Eldar player (yes I know I've just bought some Harlequins, but they're so pretty!), but could the craft in the top left be the Starweaver?