Not sure if your question meant which is the beast race for archer and mage together or separate, but I'll do both.
Wood Elves are better suited for archery due to their high starting agility and speed.
IMO Bretons are better suited for mages because of their race resistance to it, however High Elves have a bit more starting Magicka at the cost of increased elemental damage to them.
I've turned a High Elf into an archer/mage, but like someone has already said, it would take a bit work. If this helps, I still remember my character setup for that one, since I don't have it anymore.
Race - High Elf
Birthsign - Atronach ( there's a trick to it, you just gotta find it )
Main Skills - Alchemy, Restoration, Mysticism, Marksman, Mercantile, Illusion and Hand 2 Hand. I know this seems like a random set of skills but they were picked for a reason.
Toadsie2S