The current model of mobile processes in occam-π implements a single interface for host processes to use. However, different hosts holding different kinds of resource will naturally require different interfaces to interact with their visitors. So, current occam-π mobiles have to offer a single union of all the interfaces needed and hosts must provide dummy arguments for those irrelevant to its particular calls. This opens the possibilty of programming errors in both hosts and mobile should those dummies mistakenly be used. This paper considers a revised model for mobile processes that allows many interfaces. It also proposes the concept of variant call channels, that expands on a mechanism proposed for the occam3 language, and shows a simple duality between the revised mobile processes and mobile variant call channels. An implementation of mobile variant call channels, via source-code transformation to standard occam-π mobile channel bundles, is presented. This gives a demonstration implementation for the revised mobile process model and an operational semantics. The paper is illustrated with a case study based on the Santa Claus problem, where the elves and reindeer are mobile processes.