What is the problem with inline assembly? Ever heard of LAP (Lisp Assembly Program)? It appeared in Lisp 1.5 and today every decent Common Lisp has one. The sickest one is in Corman Lisp's, where all I had to do was put parenthesis around Win32 NASM code and the fucker ran it.)
IMO, if you are going to sprinkle ASM thought the program, because it really needs to be that fast then CL is probably not the best LISP dialect for you. It's just a rule of thumb and if you only care about speed for a tiny inner loop than CL is still a great choice, but if most of the app needs to be stupid fast consider your options.
Have you heard of FFIs? Foreign function interfaces? You can call ANY OS system call from Lisp, and for user-mode shared libraries you can just load them and call their functions just as easily.
Look for some applications your code needs to be as fast as possible. When your company is writing the software and spending 50million / year on HW taking a slight speed hit to use your favorite tool is not always an option.
PS: Consider how much money Honda spends on processing power for their engines and how much a 5% speed hit would cost them to fix by buying better HW.
