Thanks for the tip. I'd seen your "eGPU candidate system list" before, and it was a useful guide. I was hoping to get something at or under 2kg though, which rules out that Lenovo L540. The MacBook Retina ticks most of the boxes, but as a Windows user it does seem slightly perverse to be buying a mac to install Windows (not least in terms of price). So instead I was looking at Dell's clone of it, the XPS 15 or the M3800. These have the wi-fi card in the NGFF slot, so even that won't be a possible route for upgrades. Other options I'm considering are the Dell e7440, which does seem to have an ExpressCard slot, (confirmation from Dell still pending), but doesn't have a quad core option. The Lenovo T440s and T440p are also options, but again lack ExpressCard slots. Given the chipset supports ThunderBolt, it's a pain that these don't have a ThunderBolt port...
