SUSE Studio and Kiwi, the appliance creation tools from Novell, can be used to create customized OpenSUSE and SLES images that run on top of Eucalyptus:
http://en.opensuse.org/SDB:KIWI_Cookbook_Own_Cloud
The first section describes how to create Eucalyptus front-end and node appliance images, and the second part, 1.4, describes how to host OpenSUSE images on your Eucalyptus cloud.