Huh. I was looking for this. For some reason I got the pirate thing too; gave up, ate dinner, tried again and it worked fine. No idea why. Or what I did differently. Only thing I can think of is I put a return in before I pasted the block the second time.
Anyway, are we absolutely sure that it's hard-coded? Admittedly, I searched through all the GameInfo files and didn't see anything that would indicate a cap in there, unless it's called something very strange...... And despite adding an extra 10 levels, once you hit 10, you can't use the upgrade capital ship thing to buy more levels and the XP no longer displays. I'm sort of curious if the display thing is simply an overlay issue? Since there are overlays for each level and for each ship. I haven't actually tried getting to 10 then going out and killing things for a while though. Maybe I'll do that later.
If it is hard-coded though... that's lame.

Would seem odd that it would be when so many other things aren't.
So I take it that no one got anywhere with this in the end? (just looked at the date :p)