Ok thanks for for confirming the playlist limitation.
As an alternative, I found that simply supplying a list of image files on the command line works same as selecting them from the Advanced Open File dialog. The files play in sequence using the default duration (10 secs)
A second problem I've run into with Slide Show streaming is that it is sensitive to the image size and image type. I'm just transcoding using vcodec=mp2v mux=ts and for example, 1024x768 jpg files playback fine at the streaming target PC but png files playback with a lot of image distortion and flickering. Also, large 3072x2304 jpg's (as are output from cameras) produce zero playback at the streaming target. If however they are resized to let's say 1280x960 or 1024x768, they will playback just fine.
Lastly, I've discovered that it is not possible to stream an audio track along with the Slide Show because input-slave=<audio file> is not working in 1.0.x, but there is a trac ticket for this issue.
Regards,
tcc