We own performancetruckproducts.com and around 20 other domains that leach off of that Magento installation. We had a hugely complicated problem between the sub domains and getting them to work with our primary domain because they were on separate servers. Rory Gallagher, a Nexcess support specialist, spent ~2 hours on the phone with me getting it figured out. He was extremely patient and willing to help with whatever new issues came about.