I've heard reference of the SEA loop running from Bangkok north into Laos then over to Vietnam then south along the Vietnamese coast across into Cambodia and then eventually back to Bangkok. Maybe that's the reference?
Besides the SEAsia Loop that MADMAC talks about I've had conversations about the Northern Laos Loop and the Southern Laos Loop.
Northern - (Vientiane-Vang Vieng) Luang Prabang-Phonsavan-Sam Nuea-Nong Kiaow-Luang Nam Tha-Luang Prabang . . . roughly
Southern - Pakse-Bolaven Plateau-Champasake-Si Phon Don (a strange "loop")