In Australia, a pilot can be certified as an ICUS pilot (In Command Under Supervision) within a company. This requires an entry in the companies operations manual before the pilot can supervise another pilot operationaly. This certificate must also stipulate what type of aircraft he/she is able to supervise in. What it basically means is that you can jump in a light single or a heavy twin with an ICUS pilot and log it as 'in command under supervision' so long as the other bloke is certified on the type of machine as an ICUS pilot.
ICUS time is classed as command - but you never feel as if it is because you have this bloke beside you who can make decisions. Also we usualy have a seperate column in the log book for this sort of time.
Icus time is very attractive for a low time bloke, but its a company thing, so may not be open for every one.
Cheers.