Here's my profession setup, and yes I am levelling them as I go:

Paladin: Skinning/Mining
Shaman1: Enchanting/Leatherworking
Shaman2: Leatherworking/Tailoring
Shaman3: Herbalism/Alchemy
Shaman4: Alchemy/Tailoring

The basic idea here is to have all the gathering professions and then 2 tailor/leather/alch within the group to maximize combine opportunities at 70.