Well, the HP48 and HP49 (and their descendants) have
binary/octal/hex
 numbers, boolean (bitwise) functions, shifts, rotates, etc. But the true
 HP 'Programmers Calculator' is still the 16C.... Pity it's so hard to
 find 
 Well, I'm specifically *not* looking for a graphing calculator, and 
 
 Why not? You don't have to use the graphing functions, and the fact that
 the machine displays several stack levels (4 on the 48, 5 on the 49) is
 a definite bonus.