Here is a experimental branch of the mainline kernel with some backported patches that will be coming from stagin-next, hid and the network area where some of the drivers Hyper-V have left staging as of December 2011. So with the release of 3.2 sooner or later, you can fetch a kernel that has:

• SCSI hot plug / remove
• netvsc network promiscuous mode
• netvsc and hid out of staging
• A couple of bugfixes

Get my branch on gitorious.org

I plan to kind'a backport most of the later patches until 3.3 is finished as they don't break building - I'm quite positive with 3.4 most of Hyper-V code will have left staging and reached a maturity for other distributions to enable drivers in default kernel builds. If you're a admin that has to manage Linux on Hyper-V - other than SLES/RHEL or CentOS - now you should be asking your distributions to enable these modules (at least hyper-v bus with 3.2)