I did a visual comparison, and here it is how it turned out:
http://myhaiku.org/haiku/haiku-logo_font-comparison.png
Please note that the Limerick font is a bitmap, so it may be not very
accurate. However IMHO, from an overall balance, thickness and shape
POV, Limerick looks the closest that I have seen so far to the font used
in the Haiku logo.
Thank you for the visual comparison. I did some searching and the
problem is not the font family, but the weight. The specific font used
was Futura Medium, also called just regular Futura. Futura Book has
slight differences -- as you pointed out -- besides just the general
thickness of the letters. The connection of the capital K is different
in the two weights. There may be some further tweaking (kerning, etc.)
that you might have to do, but it is the one. You can see a preview of
the specific font at
http://typenav.fontshop.com/details.asp?GIFID=520369
