Remapping Trig Keys?

[jfrench]

Seems like a flaw in the 89 keyboard layout for daily use is that the trig keys are "2nd" keys, i.e., it take two keys to execute any trig function.
It also seems that there should be a relatively straightforward way to remap them to switch the y,z, and t keys with the sin, cos, and trig functions for routine calculations, and then switch them back for use with CAS etc. Ideally the display would indicate which mode was active when the trig was switched to the primary key function, and ideally it would only take a couple of keystrokes to make the switch.
I can do rudimentary basic programing but don't know anything about assembly, and I think this would need to be done in assembly. Correct?
Has anyone done this? Is there an applet that can be distributed and downloaded? If the previous answers are "no", then does anyone know if this is even possible.