Well the topic says it all. Can I use google web toolkit to generate my views to be used in Castle Monorail project and render it through nvelocity view engine. Is it at all possible?
I don't know of anyone that has tried this, but GWT is a server-independent technology so in principle I don't see why it wouldn't work. GWT needs some server-side plumbing which you'll probably have to write yourself (again because I haven't found anyone that has done this before).
You might want to check out Script# which is similar to GWT but you code in .Net, it has MSBuild support, Visual Studio integration, etc.