We have recently added a new feature to the Alfresco Repository that allows custom models to be updated dynamically without requiring a server restart. Additionally, the Web Client UI can also be customised without a restart. This means for example that new types, aspects and properties can now be added dynamically. Also, new workflow task models can be deployed at runtime.
Can you please describe you use-case in more detail ?
What do you want to 'reload' remotely - messages or Explorer web client (Explorer) config or … ?
Dynamic models themselves do not need a reload as such (assuming they have been deployed and activated). Please refer to RepoAdminService … one option might be to wrap this in custom Java-backed web script(s).