Unity3D: Script to merge multiple GUISkins into a single GUISkin with multiple custom styles.

GUIMerge.cs

using UnityEngine;
using System.Collections;
using System.Collections.Generic;
using System.Reflection;

public class GUIMerge : MonoBehaviour {

  public GUISkin primary;

  public GUISkin[] skins;

  // Use this for initialization
  void Start () {
    var skin = skins[0];

    foreach(PropertyInfo propertyInfo in typeof(GUISkin).GetProperties()) {

      if (propertyInfo.PropertyType == typeof(GUISettings)) {
        var settings = (GUISettings) propertyInfo.GetValue(skin, null);

        primary.settings.cursorColor = settings.cursorColor;
        primary.settings.cursorFlashSpeed = settings.cursorFlashSpeed;
        primary.settings.doubleClickSelectsWord = settings.doubleClickSelectsWord;
        primary.settings.selectionColor = settings.selectionColor;
        primary.settings.tripleClickSelectsLine = settings.tripleClickSelectsLine;
      }
      else {
        propertyInfo.SetValue(primary, propertyInfo.GetValue(skin, null), null);
      }
    }


    var styleList = new List<GUIStyle>();

    for (int i=0; i< skins.Length; i++) {
      skin = skins[i];

      var name = skin.name;

      foreach(PropertyInfo propertyInfo in typeof(GUISkin).GetProperties()) {
        if (propertyInfo.PropertyType != typeof(GUIStyle))
          continue;

        var style = (GUIStyle) propertyInfo.GetValue(skin, null);

        Debug.Log(style.name);

        var newname = name + "_" + style.name;

        var newstyle = new GUIStyle(style);

        newstyle.name = newname;

        styleList.Add(newstyle);
      }
    }

    primary.customStyles = styleList.ToArray();
  }
}