I have the same crash on i219V2 with very large network transfers to my NAS (over 20 Gigs or so). Reboot is the only way to bring the network back.
Just tried the latest driver you posted (2.1.0d2) and same issue. I can post more debug info if needed, but i figured its probably the power management thing you mentioned?
Everything else works perfectly though, thanks very much for your work on this!
EDIT: oof quoting didnt work. referring to genzai's post here: http://www.insanelymac.com/forum/topic/304235-intelmausiethernetkext-for-intel-onboard-lan/page-22?do=findComment&comment=2212902