[M.A.D.M.A.N.]

Не вариант?

Код:

type
  IMyIntf = interface
  ['{D5901C23-79CD-45A7-904B-5966ACE5ACCF}']
  end;

  TMyIntfClass = class(TInterfacedObject, IMyIntf)
  private
  public
    destructor Destroy; override;
  end;

procedure TForm1.btn1Click(Sender: TObject);
var
  foo: array of IMyIntf;
  i: Integer;
begin
  SetLength(foo, 4);
  for i := 0 to 3 do
    foo[i] := TMyIntfClass.Create;
end;

{ TMyIntfClass }

destructor TMyIntfClass.Destroy;
begin
  ShowMessage('destructed');
  inherited;
end;

"К массивам интерфейсов у меня претензий нет" expected;

Код:

procedure _FinalizeArray(p: Pointer; typeInfo: Pointer; elemCount: Cardinal);
{$IFDEF PUREPASCAL}
var
  FT: PFieldTable;
begin
  if elemCount = 0 then Exit;
  case PTypeInfo(typeInfo).Kind of
    tkLString: _LStrArrayClr(P^, elemCount);
    tkWString: _WStrArrayClr(P^, elemCount);
    tkVariant:
      while elemCount > 0 do
      begin
        _VarClr(PVarData(P)^);
        Inc(Integer(P), sizeof(Variant));
        Dec(elemCount);
      end;
    tkArray:
      begin
        FT := PFieldTable(Integer(typeInfo) + Byte(PTypeInfo(typeInfo).Name[0]));
        while elemCount > 0 do
        begin
          _FinalizeArray(P, FT.Fields[0].TypeInfo^, FT.Count);
          Inc(Integer(P), FT.Size);
          Dec(elemCount);
        end;
      end;
    tkRecord:
      begin
        FT := PFieldTable(Integer(typeInfo) + Byte(PTypeInfo(typeInfo).Name[0]));
        while elemCount > 0 do
        begin
          _FinalizeRecord(P, typeInfo);
          Inc(Integer(P), FT.Size);
          Dec(elemCount);
        end;
      end;
    tkInterface:
      while elemCount > 0 do
      begin
        _IntfClear(IInterface(P^));
        Inc(Integer(P), 4);
        Dec(elemCount);
      end;
    tkDynArray:
      while elemCount > 0 do
      begin
        _DynArrayClr(P);
        Inc(Integer(P), 4);
        Dec(elemCount);
      end;
  else
    Error(reInvalidPtr);
  end;
end;

Можно финалайзаррэй на свой подменить.