Here's the setup:
-32bit Windows 7 Host O/S, recognizing only ~3GB of 6GB RAM
If I virtualized a 64bit guest using VMWare, will it be possible for it to address the full ~6GB of RAM, or am I constrained to what my 32bit host can see?
You're constrained to what the 32bit host can see. Even with PAE, a single process can only use ~3GB of RAM, so your guest(s) will be limited to that.
If you are using VMware Workstation for virtualisation, the only way to allocate RAM >4GB for a guest VM is to run a x64 Host.
You better use "true" virtualisation by installing Win 2k8 server and activating hyper-v or VMware ESX.