The following formats do not have an icon in Nautilus:
And, some of my older documents are missing their thumbnails, all of which are either .odt or .odp.
I just purged and reinstalled LibreOffice today...could this be the reason why?
Edit: Sorry about my vagueness
I am on Ubuntu 11.10, using LibreOffice 3.4 340m1(Build:402) that comes by default in the repos.
Here's a screenshot of what I see for these formats.