HwndHostを継承してHWND (native window handle)を作ってみたサンプル! 別プロセスから描画したりもできるので、自由なことができる(にやにや)。プロセス間通信は別途必須。 ちなみにほぼコピペ https://msdn.microsoft.com/ja-jp/library/ms752055.aspx

VideoHost.cs

using System;
using System.Runtime.InteropServices;
using System.Windows.Interop;

namespace Testsuruo
{
	public sealed class VideoHost : HwndHost
	{
		private IntPtr hwndHost;
		internal const int
  WS_CHILD = 0x40000000,
  WS_VISIBLE = 0x10000000,
  LBS_NOTIFY = 0x00000001,
  HOST_ID = 0x00000002,
  LISTBOX_ID = 0x00000001,
  WS_VSCROLL = 0x00200000,
  WS_BORDER = 0x00800000;

		protected override HandleRef BuildWindowCore(HandleRef hwndParent)
		{
			hwndHost = IntPtr.Zero;

			hwndHost = CreateWindowEx(0, "static", "",
									  WS_CHILD | WS_VISIBLE,
									  0, 0,
									  (int)ActualWidth, (int)ActualHeight,
									  hwndParent.Handle,
									  (IntPtr)HOST_ID,
									  IntPtr.Zero,
									  0);

			return new HandleRef(this, hwndHost);
		}

		protected override IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
		{
			handled = false;
			return IntPtr.Zero;
		}

		protected override void DestroyWindowCore(HandleRef hwnd)
		{
			DestroyWindow(hwnd.Handle);
		}

		[DllImport("user32.dll", EntryPoint = "CreateWindowEx", CharSet = CharSet.Unicode)]
		internal static extern IntPtr CreateWindowEx(int dwExStyle,
											  string lpszClassName,
											  string lpszWindowName,
											  int style,
											  int x, int y,
											  int width, int height,
											  IntPtr hwndParent,
											  IntPtr hMenu,
											  IntPtr hInst,
											  [MarshalAs(UnmanagedType.AsAny)] object pvParam);
		[DllImport("user32.dll", EntryPoint = "DestroyWindow", CharSet = CharSet.Unicode)]
		internal static extern bool DestroyWindow(IntPtr hwnd);
	}
}