Hi swehoster.
Has your networking issue been resolved? Are you still experiencing dropped packets from the VM's? I ask as I just came across your message. Have you updated the IBM FW and driver for the adapter? IBM needs to provide you their latest approved and supported driver and firmware. Do not download the driver and fw from Emulex's website as they are different drivers and fw.
I notice in your text you mention 4 vNICs to each blade so it sounds like you are configured for Virtual Fabric Mode or also called vNIC1 mode. As for load-balancing since we are using static LAG are you selecting ip-hash in vSphere? what have you tested? Check that your ports for your static LAG are configured the same (e.g. speed, duplex, etc..). Last, have you logged a call into IBM support.
I saw some designs from Hany Michael a few years back that have been useful as well just to get a sens of the design.
VMware vSphere on IBM BladeCenter H – (Part 2 of 2) | HYPERVIZOR
Let me know where you are with getting it working.
--Alex
www.ImplementersLab.com