Current June 2016 minimal installation images are missing drivers necessary for installing Gentoo as a Hyper-V guest. Hard drives and ethernet devices are not being detected.
https://gitweb.gentoo.org/proj/releng.git/commit/?id=cd39c541be8a039bc2f561364a7eedcee90e3285 This should be fixed in the next build.
Closing as we've built a few CDs since.