Enumeraciones de banderas grandes en C#

¿Por qué no simplemente hacer:

public enum MyEnumeration : ulong 
{ 
    Flag1 = 1, 
    Flag2 = 1 << 1, 
    Flag3 = 1 << 2, 
    Flag4 = 1 << 3, 
    .
    .
    .
    Flag30 = 1 << 29, 
    Flag31 = 1 << 30, 
    Flag32 = 1 << 31
}

Podría escribir una plantilla T4 para generar la enumeración:

Plantilla (MyEnumeration.tt)

<#@ template language="C#" #>
<#@ output extension=".cs" #>
using System;

namespace MyNamespace
{
    [Flags]
    public enum MyEnumeration : ulong
    {
<#
    ulong value = 1;
    for(int i = 1; i <= 64; i++)
    {
#>
        Flag<#= i #> = <#= string.Format("0x{0:X8}", value) #>,
<#
        value = value << 1;
    }
#>
    }
}

Código C# resultante (MyEnumeration.cs)

using System;

namespace MyNamespace
{
    [Flags]
    public enum MyEnumeration : ulong
    {
        Flag1 = 0x00000001,
        Flag2 = 0x00000002,
        Flag3 = 0x00000004,
        Flag4 = 0x00000008,
        Flag5 = 0x00000010,
        Flag6 = 0x00000020,
        Flag7 = 0x00000040,
        Flag8 = 0x00000080,
        Flag9 = 0x00000100,
        Flag10 = 0x00000200,
        Flag11 = 0x00000400,
        Flag12 = 0x00000800,
        Flag13 = 0x00001000,
        Flag14 = 0x00002000,
        Flag15 = 0x00004000,
        Flag16 = 0x00008000,
        Flag17 = 0x00010000,
        Flag18 = 0x00020000,
        Flag19 = 0x00040000,
        Flag20 = 0x00080000,
        Flag21 = 0x00100000,
        Flag22 = 0x00200000,
        Flag23 = 0x00400000,
        Flag24 = 0x00800000,
        Flag25 = 0x01000000,
        Flag26 = 0x02000000,
        Flag27 = 0x04000000,
        Flag28 = 0x08000000,
        Flag29 = 0x10000000,
        Flag30 = 0x20000000,
        Flag31 = 0x40000000,
        Flag32 = 0x80000000,
        Flag33 = 0x100000000,
        Flag34 = 0x200000000,
        Flag35 = 0x400000000,
        Flag36 = 0x800000000,
        Flag37 = 0x1000000000,
        Flag38 = 0x2000000000,
        Flag39 = 0x4000000000,
        Flag40 = 0x8000000000,
        Flag41 = 0x10000000000,
        Flag42 = 0x20000000000,
        Flag43 = 0x40000000000,
        Flag44 = 0x80000000000,
        Flag45 = 0x100000000000,
        Flag46 = 0x200000000000,
        Flag47 = 0x400000000000,
        Flag48 = 0x800000000000,
        Flag49 = 0x1000000000000,
        Flag50 = 0x2000000000000,
        Flag51 = 0x4000000000000,
        Flag52 = 0x8000000000000,
        Flag53 = 0x10000000000000,
        Flag54 = 0x20000000000000,
        Flag55 = 0x40000000000000,
        Flag56 = 0x80000000000000,
        Flag57 = 0x100000000000000,
        Flag58 = 0x200000000000000,
        Flag59 = 0x400000000000000,
        Flag60 = 0x800000000000000,
        Flag61 = 0x1000000000000000,
        Flag62 = 0x2000000000000000,
        Flag63 = 0x4000000000000000,
        Flag64 = 0x8000000000000000,
    }
}

Para editar plantillas T4, le recomiendo que use un complemento de editor T4 como este (esto le brinda resaltado de sintaxis e Intellisense)

Usa 1UL así

[Flags]    
    public enum EventType : ulong
    {
        f1= 1,
        f2= 1 << 1,
        f3= 1 << 2,
        ......

        f... = 1 << 30,
        f... = 1UL << 31,
        f...  = 1UL << 32        
    }