In 2008 and 2009, Warner Bros was in the process of creating a CGI Thundercats animated movie (an original story expanding on the events of the first episode according to the rumor). But seems like the project has since been shelved... It's quite a shame because those Thundercats concept arts are rather tantalizing:
"ThunderCats follows the adventures of the eponymous team of heroes, cat-like humanoid aliens from the planet of Thundera. The ThunderCats are forced to evacuate after their homeworld comes under siege by the fearsome reptilian Mutants of Plun-Darr."
The cartoon TV series was awesome. But it's time to revamp the Thundercats and make a new movie with the latest technologies! Just think about a Thundercat movie with the same special effects as in James Cameron's Avatar: how awesome that would be! But even if they were to do the film in CGI only, that'd be great too.
Let's hope that the execs at Warner Bros will greenlight the Thundercats movie soon!