This second article seems to indicate that for the free hypervisor (ESXi 5.0?), the previous 8GB limit is lifted, it's now a much more reasonable 32GB of physical RAM. But then again, notice this comment that was quickly posted:
Question of clarification, regarding the free ESXi version: It says vRAM allocation is now 32 GB, but there's that asterisk saying limited to 32 GB. The FAQ (which looks like it was updated) states it's still at 8 GB, with a limit of 32 GB of pRAM?