Ah I missed the part about DIY - that sucks though.
You seem to be familiar with PCIe 2 though, so now I'm wondering - is there a chip that could convert the 1x PCIe 3 lane into a 2x or 4x PCIe 2 set of lanes? Also, worst case, if you really wanted to use this chip, couldn't you just use the chip with PCIe 2 (albeit slower, but I think revisions of PCIe are supposed to be cross compatible)?