With IBM servers, as you have already noted, this is currently not supported. Currently NIC Teaming is only supported with HP Servers and adding the same feature to IBM servers might be on RoadMap. With Windows based CMs as well, NIC Teaming is only supported in a few servers and was added to OS 2000.4.2 whereas with HP Servers they did exist much earlier. This would be because of driver testing with is done by Cisco when the same has been provided by the respective manufacturers.
I think you might want to contact your Cisco SE/AM to find out if supporting the same with IBM Servers is on the roadmap or not.
Hope this helps