No you can't create one with Plazmic just yet.  The new Crossbar theme is one of a kind (for now).  The first "Middle Zen" theme to grace a Blackberry desktop, the Crossbar is definitely one to check out.  Boasting 7 home screen icons (the most of any Zen theme) and docked messages, calendar and call log icons, it actually scrolls (carousel style) as opposed to just moving to highlight each icon. The docked apps show a preview below the icons when highlighted, much like a Today style theme.  Crisp and clear with easy to read icon and fonts, it's a theme to check out.  It's currently available from BPlay for $6.99.

Before you rush out to buy it, head on over to this Forum Thread. Most brand new themes tend to have a few little "bugs" that got missed in QA, and this one is no different. It seems for one Pearl user, the date at the top is getting cut off. Give it a day or two and any glitches should be remedied 100%. Also keep in mind the fonts in the menus, dialogs, and list boxes cannot be changed via the Screen/Keyboard settings (not a bug, but a limitation to the theme).