export PS1='$PWD [$?] \\u@\\h \\$ 'Gives me:
/home/gfolkert [0] gfolkert@ren $ blahblah
bash: blahblah: command not found
/home/gfolkert [127] gfolkert@ren $ mkdir foo
/home/gfolkert [0] gfolkert@ren $ touch foo/foofoo
/home/gfolkert [0] gfolkert@ren $ rmdir foo
rmdir: foo: Directory not empty
/home/gfolkert [1] gfolkert@ren $ rm -f foo/foofoo
/home/gfolkert [0] gfolkert@ren $ rmdir foo
/home/gfolkert [0] gfolkert@ren $
I like it... prolly going to change a few things too.