As shamp00 points out, a more maintainable alternative to Object Mother is the Test Data Builder pattern. Apart from NBuilder, you could also consider AutoFixture, which also implements the Test Data Builder pattern.
It'll enable you to create test instance like this:
var sc = fixture.Build<SomeClass>().With(x => x.Foo, "Foo").Build();
as well as many other features; the above example really only scratches the surface.