Primer is one of my favorite films. Director Shane Carruth famously made it for just $7,000 and the film found release in 2004, winning the Grand Jury Prize at Sundance that year. Carruth has been fairly quiet since then but he seems to be working on a new film called A Topiary. From a 2010 article on io9:
The website for now is just a place mark as financing has yet to be completed. I’m cautiously optimistic that this can happen soon and couldn’t be happier with the filmmakers that have committed to the project so far.