Shellcode from ASCII

[martin rakhmanoff <jimmers () yandex ru>]

Hello


Usually when coding exploits one needs to escape null bytes in shellcode. 
To do this XOR is often used. My question is: is it possible to escape not 
only null bytes but also non-ascii bytes?
In other words is it possible to have shellcode (for Windows 2000/XP/2003) 
that consists of bytes with codes 0x21-0x7e?

Thanks
Martin