I don't think your list is very long. I know they used to make a Sony CDP with optical out, but really have not looked for a year or so.
I suggest using the search function here on HeadFi and google on the web.
I would not be surprised to learn that for the price you might find similar function and sound quality from a plug in CD player, or better from a used one.
I recently purchased a Samsung DVD player for a bedroom at the beach house because it was small (9x9 inches I think) for $100. This is a half or third of the price I remember of the portable CD player.
Portable SPDIF sources in general are difficult to find and power. Doable though, as a search here would produce. For myself, for the short periods of time when a portable music system is needed, I find sound quality from an iPod/LOD/Hornet/IEM to be most satisfactory, and much less fuss than carrying CDs. But there are many folks here who lug their "transportable" systems with them, and love it.
