On AIX from what I recall you do get the GNU tools as an "optional" extra but they're completely ancient. Back in 2005 when I was sitting on AIX versions of make and sed and so on were 5 years old I think.
And silly me, I had to try and build a linux application on it. No big deal right, Unix is Unix? Not a chance, first I had to bring perl and grep and friends to more recent versions before I could even build it. But I couldn't even get that far.
Does vmstat exist on HP-UX? I know it's not fantastic but when you got nothing better..