But what about the Shimano ones? They're countersprung - so rather than make releasing the cable as hard as pulling it, they assist the pull.
When switched to friction though, they have a kind of micro-index feel, similar to a left Ergolever (but much softer), so I'm not sure they'd be suitable for friction-shifting a 9 or 10spd perhaps.
Available in a few shapes...
Old style
Slightly different
Tiagra
SL-R400
Late 80s