If your trying Hyper-V Live Migration with iSCSI there are some setup requirements that I'm not remembering off the top of my head that you need to do with iSCSI Initiator and storage to make sure the LUN can hop to the other server. Normally targets are initiator specific, and with different SAN software you perform the steps differently to support clustering of the LUN/volume.
I would think your storage vender would have documentation on the clustered storage part, and Hyper-V Live Migration would have documentation on the things to check to ensure the LUN "hops" from one server to another.
I also remember in 2008 R2 clustered shared volumes (many nodes write to one volume) is a good thing, allowing you to store all VM's on one LUN rather than their own.
Yes I've seen migrations simultaneously in opposite directions, it may have been Quick Migration though.
Lastly the big no no is to have the host NIC and the iSCSI NIC be the same one. Really in your scenario you want at least three, one dedicated to host, one dedicated to guest network access, and one dedicated to iSCSI on host. Microsoft actually recommends 4, with the 4th dedicated to Live Migration. http://technet.microsoft.com/en-us/library/ff428137(WS.10).aspx