Well so far I've not noticed any issues with WB7 in Vista Home premium x64, all seems to be working as it should be with a variety of skins... even the wbconfig interface is complete, whereas in Win 7 the right side is cut off slightly.
What I have noticed with Butch123's Clear Black blind in Vista is that the shutdown.logoff/restart buttons are right at the bottom of the start panel next to the search bar: however, in Win 7, while the search bar appears normally, the button area to the right is blank/backed out. This occurs with most but not all WB's
Now while this may be the result of Vista having 3 buttons and Win 7 having just the shutdown button with a mouseover for other options, I'm not having the 'no buttons' issue with skins that place them slightly higher up the right-hand panel: eg, the button and mouseover appear as normal in Win 7 when using Vampothika's Mysteria Vista, which displays these buttons slightly higher up the panel in Vista.
To me, it's like the buttons in Win 7 are being relocated on the panel and cannot appear as normal, so I'm wondering if it's also a resolution thing, particularly if one is using a regular taskbar instead of the 'superbar', and have Workshelf docked above the regular taskbar. Currently I'm running at 1680 x 1050 on a 22" monitor, if that makes any difference.
I will mess around with the stteings a bit to see if I can answer these questions myself, but hopefully my thoughts (being a non-skinner) are helpful in resolving the issue for all.
