I have a bunch of notes and ideas for something that will eventually become a coherent game. It won't be a retro-clone specifically, but it'll cover some of the same ideas of rulership and domain play that OSR touches upon, as well as some of the same adventure feel probably. we'll see.
One of the ideas I have been throwing around is a game where you do not have ability scores as such.
The game assumes that everyone is perfectly average in most areas. If you are not, you'll have a specific character trait that shows the specific way you are not average.
A woodsman who is fairly strong might manifest that as an increased carrying capacity. Or it could be a bonus to melee damage. Or maybe he can pick up and hurl an opponent. Maybe its more than one item.
A character that is "intelligent" may have exceptional problem solving abilities, or an excellent eye for details or any of a number of other things.
When creating the character, rather than rolling up numerical values, you'd select a handful of traits that make up your character, and reflect the specific ways he or she is above (or below) average in the world. Two strong characters may not apply their strength in the same way.
Obviously, you'd need a pretty healthy list of traits, and they'd probably be arranged by "ability". So you'd have a list of Strength abilities for example. This would mainly just drive character generation and make it easier to pick things out that work for your specific character type. Of course, there'd be a random option as well.
So an example "ranger" type might have the following:
Persistence (+10% travel distance daily)
Keen eyes (missile range +10%, automatic roll to spot concealed enemies)
Loner (-10% to social rolls, +1 to combat initiative)