HOUSTON, Jan 4 (Reuters) - Luxe Energy LLC said on Thursday it had received an additional $296 million from its private equity backers to buy and develop acreage in the Permian Basin, the largest U.S. oilfield stretching across Texas and New Mexico. NGP Energy Capital Management is increasing its funding for Luxe and a related company to $820 million, up from a previous commitment of $524 million.