Hmm. GUMSHOE One-2-One RPG rules.

Well, THIS looks interesting:

…although I didn’t come to that conclusion until I saw this bit at the main page:

Can’t find an entire game group who can play when you can?
Want an intense head-to-head gaming experience?
Play face to face.
Or take advantage of its superb fit with virtual tabletops to play online.

Bolding mine. Yeah, that sounds like it’d be a handy tool to have. I look forward to seeing the published version.