Hi..
I think for average VM in average company u need a VM with1 vCPU 2GB RAM right..??
If we called that a slot ..u can have around to 25 slots (with ur 48 GB now).. but it depends mainly on RAM usage and performance of hosted VMs (and some how disk space) but not CPU generally at all (CPU constrain happens rarely)..
For average IOps..it depends on the application on that VM.. I don't know myself certain number...
No news about TRIM supportin ESXi 5.x versions.. but there's something somehow similar called host cache..where u use SSD drives to store SWAP files for faster paging process..which leads to higher memory over-commitment and higher consolidation ratio..
http://www.yellow-bricks.com/2011/08/18/swap-to-host-cache-aka-swap-to-ssd/
I wish it helps..
I've one Q: how much was that..I need similar one for my company..?!?!!