Rectangular Heatsink Custom Dimensions

Hey guys, i am building a labby style blue laser and i need a heatsink. I will attach a pic of the box i am using.



Basically, i need a rectangular heatsink that is about 40mm long and only 23mm tall, with considerable depth. (at least as long as the entire aixis module

Solid metal would be prefered, but anything with alot of fins is also good. I see that this is a kind of hard project box to use, but i like the slender look. But if i plan to use a vey high powered diode (9mm) i really need a good primary heatsink other than just air cooling, so if any of you guys have something, can make something, or know where to get something of these dimensions, please tell me and ill be a very happy man

Thanks!
-Matt