Can I assign individual ports on a single adapter to different vSwitches? In other words can I assign 2 ports for SAN and 2 ports for LAN on a 4 port nic?
Yes, you can. Each port can be assigned via the adapter dialog in the vSwitch configuration screen. This is a standard task...
Here's an example with a 4-port Intel card:
In the "Network Adapters" configuration page, the four vmnicX devices show up with their link and speed status.
In the vSwitch configuration, the "Physical Adapters" shows which vmnics are assigned to which switch. I don't have any assigned to the storage network defined below, but I could easily add one.
In the vSwitch properties page, you can add adapters listed as "unclaimed adapters" to a particular vSwitch. In your case, add two to your Virtual Machine network vSwitch and add two to your storage vSwitch.