LMRoman17 is installed by default in Ubuntu. The font file is lmr17.pfb.
I can use this font in the gimp, but not libreoffice writer. The strange thing is that LMRoman10 (lmr10.pfb) IS available in libreoffice. What's going on?
I have had the same problem with other sizes of the LModern family, e.g. lmroman8. I wanted to use this font for the footnote-style.
The LModern fonts are available to libreoffice and openoffice through /usr/share/fonts/X11/type1.
This directory consists of symbolic links to the font files in /usr/share/texmf, but only for size (in german "entwurfsgröße") 10.
I solved that problem by simply creating a directory /usr/share/fonts/Type1/lm and copying the content of /usr/share/texmf/fonts/type1/public/lm and /usr/share/texmf/fonts/afm/public/lm to that directory. Maybe one could use the opentype fonts in /usr/share/texmf/fonts/opentype/public/lm respectively. This directories contain all faces of the lmodern family.
You need an fc-cache afterwards.
Have you tried rebuilding your font cache? It helps in a lot of cases.