I've been working with Velocity in Portlets and DWR (version 2) and found that I had to write my own Velocity utils to allow the DWR and generic Portlets to share context. I know there are velocity portlet classes our there but they are usually for a specific system of portals. Personally, I'm trying to write velocity portlets that can load on Liferay, JBoss, or any other Portal system.
As I was searching around at the start of the project I found that there were no portlet classes for velocity based portlets that were written generically to plug into any portal system. I ended up writing a short Velocity utility class to glue the two contexts together.