Display multiple thumbnail rows in Bridge Filmstrip Content view?

No, it is not possible AS IS.

The catch here is that if you choose a vertical orientation for the thumbnails, they will populate left to right, top to bottom. However, if you select horizontal, they will go from left to right, period. 

On the other hand, if, while you're in the Filmstrip view, choose the vertical orientation, you'll get what you want. The smaller the thumbnail, the more vertical rows you'll get. Note: you cannot save this and make it a THE Filmstrip Workspace. However, you can save it with a different name (such as MY Filmstrip), and you're good to go.