Too much code is copy/pasted from empathy-account-widget-jabber.c to other account modules, I think it's possible to have one single module with a generic enough API that can manage all cases. I think glade file are still needed for each protocol but we can have an API like:

GtkWidget *empathy_account_widget_new (glade_file,
    "widget_name_1", "account_param_1",
    "widget_name_2", "account_param_2",
    ...etc...
    NULL);

With a mapping between widget and account parameter it's possible to assign widget's value to the account param.

Possibly that could be done in empathy-account-widget-generic.[ch], if glade_file==NULL it generates a default UI like it does right now, otherwise it uses the provided glade.