Very interesting. We're currently working on a quick project to test integrating Hazelcast into a distributed server to use as a queue. Did you look at it by any chance? Curious if it was missing something that you needed.
This project sounds promising for that kind of application but wont know until I try it out.
In our case, we want to be having a very small number of queues that have a high rate of i/o with dozens of reader clients and writer clients.