Hi there
what does "single node cluster" mean? What is your workload like (volume? read/write distribution? concurrent users? types of graph operations?)? Different deployment strategies exist for different workloads, and really it would help if we had more info.
FYI: I wrote about "scale" and all its vague definitions on Bruggen Blog: Autocompleting Neo4j - part 2/4 of a Googly Q&A quite some time ago.
Cheers
Rik