Is it possible to statically link Objective Grid to an extension Dll?

Yes, that's also possible.  The steps are the same as for "How can I create a 32-Bit extension Dll that uses Objective Grid?".

Additionally, you should make some changes in testdll1:

• C/C++ settings: Make sure neither _GXDLL nor _GXEXT is specified.
  
  
• Resources: You need to include "gxresrc.h" and "gxres.rc" into the resources.

NOTE: If you link your Dll static to the grid you should avoid that your application also links to Objective Grid. Otherwise you will have to copies of the CRuntimeClass objects for both your extension Dll and your application. You should rather consider linking to OG as shared Dll in such a case.