Neat find. It would also be good for pedalboard amplifiers too.
As a practical matter, I hate machining holes through heat sink fins. This is best done on a mill, which makes it easy - but not many pedal DIYers have mills.
Here's an additional possibility for you:

The dimensions on that are 1.5" tall, 3" wide, and as long as you want it, up to about 10 feet pet stick. It's sturdy, and for a mechanical duffer like me, it machines easily and I can put footswitches and jack holes anywhere I want them with a step drill bit. A length of 11-12 inches (that is, a just-less-than-a-foot offcut)is ~$10. I believe they may even do custom cuts for a modest fee per cut.
Here's the link.
https://www.onlinemetals.com/en/buy/aluminum/aluminum-rectangle-tube-6061-t6-extruded/pid/7021Plugging the ends of extruded tubes is always a bit of a pain. One way it to make finished wood ends that fit into the holes. With the extruded rectangle, you can cut off a bit of the tube, or, if it's less than 2" tall, use 2x2" aluminum angle, and cut an L-shaped piece that just fits inside the end, and screws into the end for a flush metal end.