C#: Merging,Appending, Extending two arrays in .NET (csharp, mono)

1-merging-or-extending-arrays-in-csharp.cs

//www.technical-programming.com, lorenz lo sauer, 2013
//description: extending C# for fast and easy string extension
//note: part of a larger Open-Source Project-Codebase
//see: http://stackoverflow.com/questions/59217/merging-two-arrays-in-net

//resides in IEnumerableStringExtensions.cs
public static class IEnumerableStringExtensions
{
   public static IEnumerable<string> Append(this string[] arrayInitial, object arrayToAppend)
   {
       string[] ret = new string[arrayInitial.Length + arrayToAppend.Length];
       arrayInitial.CopyTo(ret, 0);
       arrayToAppend.CopyTo(ret, arrayInitial.Length);

       return ret;
   }
}

//example usage
	var someStringArray = new[]{"a", "b", "c"};
	var someStringArray2 = new[]{"d", "e", "f"};
	someStringArray.Append(someStringArray2 ); //contains a,b,c,d,e,f

2-generic-merging-or-extending-arrays-in-csharp.cs

//www.technical-programming.com, lorenz lo sauer, 2013
//description: extending C# for fast and easy string extension
//note: part of a larger Open-Source Project-Codebase

//resides in IEnumerableStringExtensions.cs
public static class IEnumerableStringExtensions
{
   public static IEnumerable<string> Append(this string[] arrayInitial, object objectToAppend)
   {
   	   string[] objectArray = null;
       if(!(objectToAppend is string) && (objectToAppend is System.Collections.IEnumerable)){
	   		objectArray = (string[])objectToAppend;
       }else if(objectToAppend is string){
         objectArray = new string[]{(string)objectToAppend};
	   }else{
	   		throw new ArgumentException("No valid type supplied.");
	   }
       string[] ret = new string[arrayInitial.Length + objectArray.Length];
       arrayInitial.CopyTo(ret, 0);
       objectArray.CopyTo(ret, arrayInitial.Length);

       return ret;
   }
}

//example usage
	var someStringArray = new[]{"a", "b", "c"};
	var someStringArray2 = new[]{"d", "e", "f"};
	someStringArray.Append(someStringArray2 ); //contains a,b,c,d,e,f
	someStringArray.Append("test");   //contains a,b,c,test

3-generic-merging-or-extending-arrays-in-csharp.cs

//www.technical-programming.com, lorenz lo sauer, 2013
//description: extending C# for fast and easy string extension
//note: part of a larger Open-Source Project-Codebase

//resides in IEnumerableGenericExtension.cs
    public static class IEnumerableGenericExtension
    {

        public static IEnumerable<T> Append<T>(this T[] arrayInitial, T[] arrayToAppend) where T : System.Collections.IEnumerable
        {
            if (arrayToAppend == null) {
                throw new ArgumentNullException("The appended object cannot be null");
            }
            if ((arrayInitial is string) || (arrayToAppend is string)) {
                throw new ArgumentException("The argument must be an enumerable");
            }
            T[] ret = new T[arrayInitial.Length + arrayToAppend.Length];
            arrayInitial.CopyTo(ret, 0);
            arrayToAppend.CopyTo(ret, arrayInitial.Length);

            return ret;
        }
    }

Hello, how about 6 byte[] arrays?
byte[] ID1 = { 0x46, 0x62 };
byte[] ID2= { 0x01, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
byte[] ID3 = { 0x42, 0x22 };
byte[] queryType = { 0x01, 0x10, 0x00, 0x01, 0x00, 0x10, 0x00, 0x00, 0x00, 0x00 };
....
I can not do it at all..