Another option would be to find a toggle switch that actually uses a slide switch mechanism, preferably one with open ends so you don't have to mod it, then add a solonoid or RC servo behind the panel to push the end of the slider when required.
However, I think your idea of building your own is likely to result in a superior switch, with better look and feel, and if you use a sealed microswitch for the contacts, better reliability.
Aluminium is prone to corroding and jamming if there is moisture + dirt around, so if you are using soluble cutting oil coolant or don't have a fully heated workshop, you should consider building it in steel and brass (or stainless steel and bronze for really harsh environments), avoiding steel on steel or brass on brass rubbing contact.