Hi Brian,
DBGeneric project namespace is, indeed, the whole root namespace. So if you want to add a suffix you may add it at RootNamespace (project properties). Note that as this is the RootNamespace, this will affect the DBSpecific namespace:
Root NS: MyCompany.Sales
AdapterDbSpecificNamespaceSuffix: DAL
Resulted DBGeneric NS: MyCompany.Sales
Resulted DBSpecific NS: MyCompany.Sales.DAL
Root NS: MyCompany.Sales.Generic
AdapterDbSpecificNamespaceSuffix: DAL
Resulted DBGeneric NS: MyCompany.Sales.Generic
Resulted DBSpecific NS: MyCompany.Sales.Generic.DAL
What do you want to achieve?
Have you notice that you can add additional interfaces and namespaces? (Ref: LLBLGenPro Help - Using the designer - Adding and editing entities). Also, there is a plugin to bulk-set interfaces/namespaces to entities.