I may just have hit upon one of those conflated Strands: The Norwood Builder, more particularly the ITV, Jeremy Brett adaptation, which expands the story. In Doyle's original, Oldacre burns what Holmes believed to be animal flesh to ash to simulate a murder victim, whereas in the Brett version, Oldacre lured, killed and burned a tramp, a ruse Holmes pieces together partly through a secret sign left outside Oldacre's house, and partly by disguising himself as a tramp to gather information.
Since, even 30-odd years on, Brett and Holmes remain inseperable for many (myself included), and the Brett adaptations were known for being more faithful than most (even down to matching as closely as possible the depictions of characters in the Paget illustrations), the potential for conflation seems strong.