Adding class or tag to #bodyrow

Following comments in this post about the unruliness of my CSS inserts , I've been tidying things up a bit (work in progress still).

Quite a lot of coding goes into creating different colour schemes for different pages, using Page-ID selectors. This gets confusing as more pages are added. E.g.
It would be simpler if I could replace this code with something like:
The .yellow or .blue class would need to be appended to the #bodyrow ID, because the colour scheme only varies here, not in the header or footer.

In the wordpress page editor is an options box [Page Attributes > Parent & Template], where the multicolumn option is. Ideally I'd have something similar, which allowed me to mark each page/post as either a Yellow or Blue page, which then added a suitable selector to the html.

Has anyone found a plug-in which might do this (or could be tricked into doing this)?