I have just finished my third High Definition slide show for television and have to take exception to your statement about looking "awful on TV".
I first made a Blu-Ray DVD and played it on a Blu-Ray DVD player connected to a HD television. I found the picture to be excellent but jumpy when using the pan or zoom features in the slide show software.
My next two slide shows were burned onto normal DVD media (not Blu-Ray).
When played on a Blu-Ray DVD player or a newer upscaling regular DVD, the image is excellent but without the jumping I experienced on Blu-Ray DVD media.
All the pictures were 1920 x 1080 or larger.
And the software aspect ratio was set to 16:9
The slide show software was ProShow Gold by Photodex.
The software can also be used to show video clips.
Instead of inserting a slide, you insert a video clip.
Slides and video can be inner-mixed.
But you are right, it does take some time to make the slide show, but after you make a few, it goes much faster.