Is Neo4j horizontally scalable for writes?

After reading this blog entry:
And the stackoverflow answer here:
What is the status on Neo4j's horizontal scalability project Rassilon?

I get the impression that while adding Neo4j instances to a cluster can improve availability, data redundancy, and number of concurrent reads, it does nothing to improve the number of concurrent writes due to the way Neo4j instances are clustered. Both resources indicate that the maximum number of writes is "10s of thousands per second" in a well-tuned cluster.

I'm wondering if this "10s of thousands of writes per second" limit is accurate, and if so, if there is any way at all around it. Are there different ways to configure Neo4j clusters besides the "High Availability" Master/Slave model that allow horizontal scaling of writes (even if it is at the expense of ACID compliance)? If not, are there other graph databases available that can exceed this limit and scale horizontally for writes?