We've been able to summon and switch preconfigured mounts (and appearance mounts if you're a patron) from the Icon Bar or with a hotkey for a while now. And in fact our current Tip of the Week demonstrates Remote Mount Presets.
Darq Side member Arderath mentioned in Discord that setting up buffs, gear, mount, familiar, etc., for tradeskilling versus adventuring was a bit less automatic than it could be, since the familiar preset still had to be cast from the Character window.
If you have updated to Character window v3.078+ (version 3.064+ for non-premium) we can now use the same technique to remote-summon familiars as we do for mounts. Simply replace the term Mount with Familiar in a hotkey macro or on the Icon Bar and you'll be good to go. Click the above screenshot for an example. The three commands to remote-cast familiar presets A B and C are:
show_window MainHUD.Persona.Familiar.Preset.A
show_window MainHUD.Persona.Familiar.Preset.B
show_window MainHUD.Persona.Familiar.Preset.C
I was panicking while testing because my familiar didn't appear to be changing, but then I realized I was using an appearance familiar that was overriding the look of the others. Appearance Familiar Presets are not yet available like they are with mounts. Those should be possible, but they'll have to be scheduled for another day. :)
Editor's Note: Appearance Familiar Presets have arrived: take a look!