You don't want a host made out of steel. It has terrible thermal conductivity. A 7 watt diode puts out a great deal of waste heat that needs to be removed to the surrounding air. I would use aluminum which has much better thermal conductivity and possibly a copper core which has even better thermal conductivity. A steel host won't be able to absorb the heat well or move it to the surface where the air can carry it away.
I totally agree with what Paul said - with one additional thing - from what I hear, pattern-welded steel is not generally that fun to machine as it's got inconsistent hardness going from one layer to another. And I don't know what all of those material boundaries would do to thermal conductivity - but I can't imagine it'd improve it.
If you're dead set on this material - I hope you a) have deep pockets, and b) have realistic expectations, as a host for a laser needs to be functional as well as aesthetic, and Damascus steel unfortunately only fits the latter.
You're unlikely to get anyone quoting you for a job unless you have some kind of drawing of how you want it to be - think dimensions, size of materials, etc. A damascus host is also going to be expensive as you end up wasting the hollowed out metal in the centre - and the starting material is pricey.
If you want one of the experienced machinists on the forum to take a look they'll want to know what you want in some detail before they commit
I think a damasteel host would look amazing, but its terrible for venting the heat from lasers. Have you thought about maybe a different damascus material?
There's a brass+copper mokume out there that would be much much better for lasers, and it looks beautiful when polished
Exactly, I started making a ring out of it but it accidentally cracked it when I tried to finish it
It was beautiful too.
Be very careful should you decide to use a material like copper+nickel silver damascus. When you mix metals such such as silver(noble) and copper(base) the base metal will erode away due to chemical reactions between your skin and the material.