xvideosink should work over a remote X connection, without XVideo
acceleration of course, but here's what happens:

Running "gst-player":

Shared memory unavailable, using regular images
The program 'gst-player' received an X Window System error.
This probably reflects a bug in the program.
The error was 'BadShmSeg (invalid shared segment parameter)'.
  (Details: serial 15 error_code 175 request_code 146 minor_code 2)
  (Note to programmers: normally, X errors are reported asynchronously;
   that is, you will receive the error a while after causing it.
   To debug your program, run it with the --sync command line
   option to change this behavior. You can then get a meaningful
   backtrace from your debugger if you break on the gdk_x_error() function.)

Running "gst-inspect xvideosink":

Shared memory unavailable, using regular images
X Error of failed request:  BadShmSeg (invalid shared segment parameter)
  Major opcode of failed request:  146 (MIT-SHM)
  Minor opcode of failed request:  2 (X_ShmDetach)
  Segment id in failed request:  0x1200003
  Serial number of failed request:  15
  Current serial number in output stream:  18

Inspecting videosink works fine.