What sort of sized saws are you thinking?
I have clamped the inner spikes (dawgs in your part of the World?) of some of the larger saws in a large engineers vice and started them whilst held in such a way (without bar and chain attached).
There is a multi positional chainsaw "vice" with a slotted hole arrangement and ball joint positioning to change orientation that is bench mounted and fixes to the saw via the bar studs- not sure of the exact name off hand, or even where they are available from- will try and find a picture of one.