I have posted a colour chart of silk thread called Seta Reale marketed in the UK by Coats UK.
The colour range is fantastic. It appears to be about the same thickness as Pearsalls.
It is on tubular spools and will have to be rewound onto standard wooden spools or the metallic type
used on sewing machines. With that range it will be worth the trouble.
http://www.dtnicolson.dial.pipex.com/page183.html

I have also found a range of silk by Gutermann a Swiss company, it is of a thicker gauge and the colour range
is smaller, but it could be useful. I'll post their chart on my site ASAP.