type
  TBaudRateProperty = class(TStringProperty)
  public
    function GetAttributes: TPropertyAttributes; override;
    procedure GetValues(Proc: TGetStrProc); override;
    function GetValue: string; override;
    procedure SetValue(const Value: string); override;
  end;

  ...

type

  TBaudRate = (br110, br300, br600, br1200, br2400, br4800, br9600, br14400,
    br19200, br38400, br56000, br128000, br256000);
const
  BaudList: array[TBaudRate] of string[7] =
  ('110', '300', '600', '1200', '2400', '4800', '9600', '14400', '19200',
    '38400', '56000', '128000', '256000');

{TBaudRateProperty}

function TBaudRateProperty.GetAttributes: TPropertyAttributes;
begin
  Result := [paValueList];
end;

procedure TBaudRateProperty.GetValues(Proc: TGetStrProc);
var
  i: TBaudRate;
begin
  for i := Low(TBaudRate) to High(TBaudRate) do
    Proc(BaudList[i]);
end;

function TBaudRateProperty.GetValue: string;
begin
  Result := BaudList[TBaudRate(GetOrdValue)];
end;

procedure TBaudRateProperty.SetValue(const Value: string);
var
  i: TBaudRate;
begin
  for i := Low(TBaudRate) to High(TBaudRate) do
    if BaudList[i] = Value then
    begin
      SetOrdValue(integer(i));
      EXIT;
    end;
  inherited SetValue(Value);
end;