Best practices for Domain Service classes in RIA Silverlight projects

I would like to ask whether or not is a good practice, to hold the CRUD operations for business objects, in 开发者_开发百科a single domain service class. Should we provide a domain service class for each BO?

ProductDomainService.cs CustomerDomainService.cs ...

or a single

BusinessObjectDomainService.cs

I went with a single domain object beause my model is not that complex. I would think it might be better to cluster the domain services together ie user services logging services. That kind of logical clumping would be better than 1 for each business object.