So started looking more at specs and since Standard Server 2008 is only limited to 32GB, I assume even with Hyper-V role added you can only have only 32GB total on the system.
Yes, however; you can install the standalone Hyper-V server - Microsoft® Hyper-V™ Server 2008 R2. The downside is there is no gui, but you don't have the memory limitation. You can manage it from one of your other systems and join it to your domain.
Another interesting option is to use Windows 8 Professional's Hyper-V. I am unsure if they are changed since the preview versions, but I've loaded them on Dell R720's with 96GB memory. That and Hyper-V v3 > Hyper-V v2.