WindowBlinds allows you to specify the size of certain windows elements in order to increase flexibility (especially under UIS1+ skins). You simply add a section called [Metrics] and add any or all of the 4 options below to specify the item you want to size. All 4 are effective in UIS1+ skins, only the last 2 in UIS2 skins. All measurements are in pixels.

[Metrics]
CaptionHeight =               (height of the title bar)
ToolCaptionHeight =           (height of tool window captions)
MenuHeight =                  (height of menubar)
ScrollWidth =                 (width of vertical scrollbar)
                            / (height of horizontal scrollbar)

Of course you will probably also need to adjust your frame margins to accommodate this, and you may want to adjust other items such as buttons, but it overcomes the previous lack of flexibility that UIS1 had in this area. The screenshots below demonstrate the sort of effect that you can achieve from this.