Apparently the new purchasable 4k firmware (60 Mbps) will allow footage shot with that firmware to be ingested into Vegas.

New firmware for broadcast and professional A/V equipment from Sony : United Kingdom : Sony Professional (http://www.sony.co.uk/pro/article/broadcast-products-firmware-equipment)

Vegas 13 got XAVC-L support a while ago. 100mbps is not included with this update, but may come in a later update.

Sony did not announce new 4K prosumer cameras at NAB, so don't expect a new stopgap between this and the FS7.

XAVC-Long GOP files from other cameras work fine with Vegas Pro 13 Build 444 but not the x70 yet.