Yeah, quicklook would be wicked. I've noticed that numbers offers a stripped down version of the file in the file-bundle (the *.numbers package). I think that the most quick and dirty way to get OO to quicklook is to just create a screenshot of the main window, stick it in the OO file bundle, and key that to quicklook, rather than trying to make it rich text. I think most people just want to peek, anyway. ITs not elegant, but it would work.
I've been completely jonesing for this since Leopard. Currently OO is one of the only programs I use that doesn't have this. It blew me away that even SPSS (a stats package runing on java and know for crappy mac support) has rudimentary QL.
I gave lots of latitude to the awesome devs while they worked on OF, but now that OF is shipped (and indispensible) and OG is rolling, why not spend a day or two on this, I'm sure it will translate into at least a little ROI.