I work around the power industry & aluminium cables are used widly in this industry & I believe some of the import boys are getting into it as well. There is plenty of info on the net to convert the power capability between copper and aluminium cables so you can work out what size you need.

You need to talk to someone in the industry that uses aluminium cables to get all the tricks & traps but I do know you have to clean the aluminium strands with flux & a SS wire brush right before you crimp the ends to minimise oxidation.

You are on a mission man, I wish you well.