Solution folder structure recomendation for IoC Services

Question

I VS 2008 solution IoC modules are organized now as follows:

-Modules (solution folder)
--Device (solution folder)
---MyApp.Device.Device1.Module (IoC service implementation for Device 1)
---MyApp.Device.Interface (IoC service definition)
---MyApp.Device.Device2.Module (IoC module implementation for Device 2)
---MyApp.Device....
---......
---Generic (solution folder)
----MyApp.Device.Generic.Interface (IoC service definition)
----MyApp.Device.Generic.Module (IoC service implementation for all generic devices)

This structure is derived from samples. I have noticed, that Service definition and all implementations are in the same solution folder.If I have >7 implementations, IMHO definitions and implementations can confused. Also, is this folders structure is still recommended/accepted or should be reorganized? How?