The Starbucks sample (https://github.com/MassTransit/RabbitMQ-Samples/tree/master/Starbucks) has Winsor, StructureMap, and NInject but no Unity. I don't think any of the core team uses Unity.
Though I'd start with making sure you have Unity integration NuGet package included. Check your namespaces (using MassTransit;
). It's all extension methods, and should be in the MassTransit namespace. We might have misplaced a type in the wrong namespace somewhere but my quick check of the source doesn't show any.