Экспедиция во главе с Х и при участии A, B, C gen.

[10-4]

Как бы это поизящнее перевести на англ.?
The expedition led by X and staffed by A, B, C?
The expedition headed by X and with A, B, C as members?

[itisasecret]

under the guidance of ... and with participation of / and with ... as expedition participants
"led by" sounds ok.

[Wolverine]

не развернешься тут.
The expedition was led by X. The team included A, B, and C.
The expedition team (A, B, and C) led by X ..conquered Everest.
A team of geologists (A, B, and C) led by X...

[10-4]

В результате получилось:
The expedition (X as a leader, and a team of A, B. and C) started from Golomyanny Island to the North Pole across drifting ice of the Arctic Ocean...

[Wolverine]

это в скобках не очень звучит.
тогда уже as members.
led by - стандартно.

" started from Golomyanny Island to the North Pole across drifting ice of the Arctic Ocean... " - судя по этому кусочку, я бы добавил что-то вроде слова "moving" across drifting ice. но это можно и в конце указать/ поменять.

[mikhailS]

The expedition led by X, and a team made up of A, B. and C set out from Golomyanny Island to the North Pole across drifting ice of the Arctic Ocean...
..to be never seen again...( ))

[10-4]

К счастью, у них все прошло благополучно, но с полюса они слиняли в Канаду... Так ближе.

[cyrill]

+the X (led) expedition

[muzungu]

expedition led by * and including ***

[hsakira1]

10-4, самый приемлемый вариант для вас
The expedition led by X and involving a team of A, B and C set off from the Golomyanny Island across the drifting ice of the Arctic Ocean to the North Pole.

among others, see this source
http://en.wikipedia.org/wiki/Norwegian–British–Swedish_Antarctic_Expedition

[Dmitry G]

expedition consisting of 4 members: A, B, C and their leader X

[cyrill]

не стоит 10-4 так уж диктовать hsakira1, he ain't no spring chicken here himself. :-)

[10-4]

Составляю словарь-справочник самых приемлемых вариантов. Всем спасибо.