Despite the fact that many early JBI implementations are reusing enterprise infrastructure for their implementations (e.g. JMS messaging backbones and J2EE containers), my prediction is that JBI will start invading the mobile market.
Already, people are looking to leverage JBI implementations on small footprint platforms as a means of realizing the benefits of an "enterprise" service bus, but without the overhead of the "enterprise". In this capacity, JBI is a great means of achieving service re-use , while maintaining loosely coupled composition.
For example, JBI may be the best means to inject security into a mobile application. Since JBI focuses on data flow, , a developer can just "drop in" security components, rewire the messages to first pass through an authentication and authorization engines. Without changing the app at all, it would be capable of invoking services that require digital signatures. I go through this use case here.
It is a common misconception that OpenESB is wed to NetBeans and Glassfish. This isn't the case at all. In fact, you can follow these instructions to get OpenESB up and running in a J2SE environment, with XMPP capabilities and RSS feeds!
Lots of fun. =)