No. Script are either compatable with VISTA or not. Same as skins are for 8.5 or 9.0. There is no need to imposed restrictions and it would infact limit scripters in the ability to create new features for the rest of us. Someone only has XP and so can't make a VISTA script... Sound fair that nobody gets to use the hottest new feature?
It's all fine how it is... If it bugs you that much, either setup a dual-boot machine or learn to run Virtual Desktops