Create and build an empty DLL project, that contains a resource link reference to the .res file that contains your resources.

Example:
library ResTest;
uses
  SysUtils;
{$R MYRES.RES}
begin
end.
To use you resource only DLL, simply load the dll and the 
resources
you wish to use:
Example:
{$IFDEF WIN32}
const BadDllLoad = 0;
{$ELSE}
const BadDllLoad = 32;
{$ENDIF}
procedure TForm .Button Click(Sender: TObject);
var
  h : THandle;  
  Icon : THandle;
begin
  h := LoadLibrary('RESTEST.DLL');
  if h <= BadDllLoad then
    ShowMessage('Bad Dll Load')
  else begin
    Icon := LoadIcon(h, 'ICON_ ');
    DrawIcon(Form .Canvas.Handle,  0,  0, Icon);
    FreeLibrary(h);
  end;
end;