As long as your VM uses a virtual file (as opposed to direct host disk access) it makes no difference which OS the guest is running.
Running the VM with direct host disk access (to the SSD) is fatal because both TRIM and W7 itself have no idea what the VM is doing to the host file system.
As seen from the host (W7), the VM is just another Windows application and as such, the VM disk writes are actually handled by W7. So yes, your SSD will still benefit from TRIM.
On top of that, I found that VMs and SSDs are a perfect match. Again, run the VM on a virtual disk file only and you'll be just fine.
Your second question: yes, running the Toolbox on top of a running VM will restore SSD speed (not capacity, I assumed you meant speed). However, I found that the VM will temporarily grind to a halt while the Toolbox optimizer is running so don't run the Toolbox while the VM is running time-critical tasks. Apart from that, there is no interference.
Yes I'm running both VMware and Microsoft VM on my Postville (MLC). I don't use TRIM but I run the SSD Toolbox optimizer regularly. Speed and response times remain excellent. Be warned that MLC is not rated for professional use but it works fine all the same. For company use you might consider using SLC.
Using a Sysinternals tool I monitored the VM writes. Writes are small, frequent and random. Exactly what the Postville likes best. I experience no degradation.
Hope this anwers you questions.
Thanks for the advice for the professional use of the MLC . I am not planning to use in a professionnal operational environment but rather as a proof of concept and demo ; if this is a success then we will probably move to SLC in production. Just need to lower the price of the demo kit as much as possible for now.
For my information, why did you choose to run the toolbox rather having automatically TRIM executed ? Is this because of your host OS that is not compatible. I would assume that the host is not XP/Vista/7, did you get the Intel toobox to work on a Windows 2003 Server host ?