Create the project. Add one file as Content. Unload the project and edit the *proj file manually.
<ItemGroup>
<Content Include="myfolder**\*.dll**">
<CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
</Content>
</ItemGroup>
And then in the content-ItemGroup I would replace that singe file with some MsBuild wildcard expression, *.dll, or whatever.