general design if you have many nics..you can follow the below
vSwitch0 --> eth0, eth4 (for managment and vMotion in Active/Stanby configuration). Let's say I will use VLAN 100 for management and VLAN 101 for vMotion, use multi nic vmotion
http://pibytes.wordpress.com/2013/01/12/multi-nic-vmotion-in-vsphere-5-x/
vSwitch1 --> eth1, eth2, eth5, eth6 (for iSCSI connection to the storage in Active/unused configuration) -- VLAN 102 create 4 vmkernel portgroups, each pnic will be active and other 3 will be unsed, there is no need to use the esx vswitch failover.. the psp will handle the failover,,, that is the it is depend on the multipathing policy and it will take care of the uplink failures.
vSwitch2 --> eth4, eth7 (for running VMs in Active/Active configuration) -- VLAN 103
there is no issue in using pnics of different vendors.. we also normally use this in the design. This will prevent the firmware/driver errors which may raise in the due course. So if you use intel & broadcom in the same vswitch it will be very good.. and will be a roboust design.
Jumbo frame you can use the value 9000, and it can set in the vswitch and pswitch.