I've definitely heard of it! But there's been some time in-between. There was someone I knew who got the Boren Scholarship as an undergrad in Taiwan, worked at USAID for a year, pursued a Fulbright ETA in Thailand, then later pursued a Boren Fellowship in Thailand. I'm curious to see if he ends up applying for a Fulbright research grant too, and how he made that shift from Taiwan to Thailand. Anyways, it is quite possible to receive both.