Kilobyte Constants, a Simple and Beautiful Idea that Hasn't Caught On

Eric Isaacson's A86 assembler (which I used regularly in the early 1990s) includes a great little feature that I've never seen in another language: the suffix "K" to indicate kilobytes in numeric literals. For example, you can say "16K" instead of "16384". How many times have you seen C code like this:
char Buffer[512 * 1024];
The "* 1024" is so common, and so clunky in comparison with:
char Buffer[512K];
In Forth this is trivial to add, at least outside of compiled definitions. All you need is:
: K 1024 * ;
And then you can write:
512 K allot