I was wondering if there's a way to do
#if($some.project.property == true)
some text to include here
Simple answer no. But if you really need conditions you might take a look into the velocity-maven-plugin which solve your problem but it's not intended to filter resources but your use case it might work.
<plugin> <groupId>com.googlecode.velocity-maven-plugin</groupId> <artifactId>velocity-maven-plugin</artifactId> <version>1.0.0</version> <configuration> <templateFiles> <directory>/src/main/resources</directory> <includes> <include>*.vm</include> </includes> </templateFiles> <templateValues> <test>foo</test> </templateValues> </configuration> </plugin>