well there is a hudge difference between packer/crypter and pe protector like armadillo.
well maybe u could try to mimic armadillo
they have to good shit in the world.
no cracks for their latest version
and last i heard is that the last crack took the power of a entire uni's comps to break 1 key
and by the way I tried armadillo with some viri and rootkits and kav detected them.