Да вроде можно

Сам не пробовал, но вот шо я нашел в инете
var
DLLApp: TApplication;
DLLScr: TScreen;

procedure InitPlugin(App, Scr: integer); StdCall;
begin
DLLScr := Screen;
Screen := TScreen(Scr);
DLLApp := Application;
Application := TApplication(App);
end;

procedure DonePlugin; StdCall;
begin
Screen := DLLScr;
Application := DLLApp;
end;

function CreateMDI: integer; StdCall;
begin
Result := integer(TfrmMyChildForm.Create(Application));
end;

exports
InitPlugin,
DonePlugin,
CreateMDI;