What has been changed on it? - Wheels; springs/shocks; or is all all pretty standard?
You're correct that there's no OEM adjustment other than the toe-in/toe-out from the track-rods. - Excessive toe-in is often what's wearing the outside edge of tyres on these; especially as the handling is usually set to understeer.
You can buy camber bolts, but they only add a small amount of camber; could be you've got some fitted, but they're not set because someone mistook them for normal bolts.
We've got some members who really know suspension; hopefully they can give you something more useful that this.