To get a shadow, you just have to use /writechat twice with different chat coloring. (shortcut for /writefont default) (NA2 exclusive)
For example:
/writechat &8Shadowed text!
then
/writechat Shadowed text! (with an offset)
If you're not on NA2 you'll have to do it manually or use /imageprint with a screenshot of the text you want.