Ok so have been spending some time trying to get a decent Bespin Transparent look. Now this is my first time trying to set this type of thing up let alone in Bespin so if there are any issues let me know.
Note you will need to install Bespin for this theme, here is a how to download and compile from source: [link]
Original Bespin Config that I moded was: KDE Style / Win Dec / Color Scheme: bespin-preset-collection 1 by [link]
OS: Kubuntu 12.04 x64 DE: KDE 4.8.4 KDE Style/ Win Dec: Bespin Custom Conifg by
KDE Plasma Theme: Helium One by mcder: [link] Icon Theme: kAwOken by [link] Conkyrc: conky bottom clock by [link] Covergloobus: Curl for Covergloobus by [link] Wallpaper: Field Fog Wallpaperby [link] Montiro PSD: Apple Thunderbolt Display PSD By [link]
Do you mean the menu you click in KDE that shows your apps and computer and the item to shut down and suspend and so on? If so thie look is controlled by the plasma theme you choose.
Well I have never attempted with GTK3 theme in gnome. The transparent effect is built in to Bespin KDE style. I will do some searching and if I can find anything that looks promising I will post back to you.