Email some company that make a-arms

I know metal tech use to make some http://metaltechproducts.com/A_Arms.htm
Maybe try LSR http://lsracing.com/
Fireball racing http://www.fireball-racing.com/arms.htm
Walsh http://www.walshrc.com/
JD Performance http://www.jdperformance.net/488%20Web%20Design/a%20arms.html


Or if you are feeling lucky, maybe buy some parts from JJA and make your own a-arms
 http://www.jjandaracing.com/contents/en-us/d28.html