Absence of accessibility tools within pantheon-greeter

There is a distinct lack of accessibility tools callable from pantheon-greeter. In particular a virtual ketboard (onBoard?) a screen magnifier (?) and high-contrast and large-text modes. Also, in the long-term there are probably other accessibility options (e.g colour schemes for the colour blind) that could and should be made accessible from the login screen. Although not suffering from an impairement myself I can't be confident of identifying all such shortcomings.

Much of could (and perhaps should) be developed by elementary's upstream partners (gnome, canonical, etc...) or in colaboration with them. However, implementing a virtual keyboad (onBoard with a fitting theme?) should be achievable in the short-term (Luna?) as such is already implemented in Ubuntu's LightDM greeter and (I assume that) all of the essential components are there.