Faize wrote: I simply can't afford to temporarily lose 2-4 gigabytes of disk space every time I power on a VM.
If that is the case then you either have to small of an SSD or to much on the SSD to begin with, take your pick. 
Seriously though I do not know if any of the old methods work with VMware Workstation 9, just haven't had the need for them anymore and haven't tried them, however have a look at mainMem for a reference and see what if anything will work to your liking.