I’ve made some [Squib] modifications that allows for selection of different stylesheets from within a theme without having to make continual modifications to the theme. It works for both staging and live sites. The drop-down that contains the themes lists the contents of `themes/theme_name/resources/styles` for the selected theme.
What’s confusing could be that the list of theme stylesheets will only be shown correctly after first saving the new theme and then refreshing the page. Makes sense, but I wish it would be automatic for the theme selected but not saved. Don’t worry if it sounds confusing.
Anyway it’s all wrapped up in a patch to Matt.