What I'm concerned about is OS look-and-feel and interface — system bar on the bottom with clock, trash, info on the right, menu on the left ...
Any distro running GNOME, KDE or XFCE (that is, almost any distro by default) can be easily configured in this manner.
... menu items similar to those of Windows.
For the love of God, no. This is one of the areas where Linux by and large kills Windows in terms of usability. It won't take long for them to appreciate the (mostly) logical grouping of programs in, for instance, Ubuntu's applications menu. The Windows Start menu is a nightmare by comparison.
Are there themes/skins for mainstream distributions instead?
Sure, but I wouldn't recommend them. Whilst I'm all for easing the transition, there's nothing wrong with at least acknowledging that a transition is taking place, so just give them a "normal" GNOME of KDE desktop.