What are my options for creating node types, then? Is it possible from the jcr2spi + spi2davex client at all?
You either have to do it on the server side, wait for someone to implement the missing functionality or implement the missing functionality yourself and attach patch to JCR-2454 [1] ;-)
Michael [1] https://issues.apache.org/jira/browse/JCR-2454
