I generally don't care for beam weapons, though after MODs they seem to have become very popular. My idea is for an energy weapon that has a vampirism effect. It restores back between 10% and 25% of damage to the user's mech HP. Amount stolen will depend on weapon level. Stacks with MD healing. 

Launch around Halloween and call it the Fang or something. 

If you like the idea and you can compensate me with 5% return of sales in A coins to my account.