I would not use the two 1gig in the configuration, it just makes things complicated and leads to potential problems. The two 10gig should give redundancy and bandwidth. iSCSI protocol by design is capable of MPIO, just configure iSCSI MPIO, make sure your two 10gig are connected to different switches for redundancy and you have pretty solid design.
Here is the iscsi best practises. http://www.vmware.com/files/pdf/iSCSI_design_deploy.pdf