Was just browsing the website of Steven Chorney (an artist who has a lot of overlap with Drew Struzan and did some art for a The Dig advert) and noticed some concept art for an Indy game that "never came to fruition" (not the one mentioned in OP presumably, but I thought it'd be neater to post in an existing thread!). There's five of them at the top of the page, some generic stuff but also a fair few details of props, locations, characters etc:
http://www.stevenchorney.com/#ConceptArt