IVIemories I remade one of my favorite old designs and think it'd be a great enemy in BH mode.
Name: Eldritch Spear
Cost: 1,465,350
Strengths: Good amount of focused fire especially at close range. Fairly agile. Durable in a "head on" fight.
Weaknesses: The missile launcher segment is unprotected from the sides and if it is damaged and explodes the "head" of the craft will be severed. Well aimed railgun shots to the middle of the front of the craft can also do a lot of damage. Also the rear facing thrusters are exposed.
Edit: Wanted to add some more info after testing this ship against all of the larger built in ships. It's able to defeat all of the built in ships except for the Terror and Valor, and it has a close match-up against Cerberus that it usually wins. The A.I. can't take advantage of the designs biggest weakness though so I think players will have an easier time defeating the Eldritch Spear as long as they are smart about where they target.