You act like this is Build 2011. In other words, you are behind the times.
- is there themes for metro (I call it metro) like if you work on chrome auto parts all day - and you want a chrome/silver metro - is there one?
You can customize the main colors for Windows. If you are looking for more than color, like glassy or reflective or gradient effects, then no. Of course, apps can do it if they want, but that's up to the app designer.
- why all the RGB basic colour palette? is there a - theme - for pastel or muted colors? B&W simple style choices?
It isn't limited to RGB. You most certainly can have pastels, muted colors, etc., and Windows 8.1 offers a larger selection.
- can I run all of metro in a window - like media centre exactly. I have used utils that did this - poorly