[img]Why not go with the Mantic Forgefathers? They have legs that are already farily widely set and separate arms that you could position at various angles. The torsos aren't separate, but the only dwarves with separate torsos that I know of are the standard
GW Dwarves.
Here's the mantic Dwarf sprue. Though not yet released, the Forgefathers are likley a reworking (new torsos and arms) of this sprue.
http://www.totalwargamer.co.uk/blog/wp-content/uploads/2010/08/mantic-games-dwarf-ironwatch-sprue.jpg
As for bikes, Hot wheels has a few that might work, though you'll have to have a dremmel if you want to mod them.