you can, but at $4 for a new spray bar, why bother?
if you made your own by drilling or melting
holes, you'll never get the water to spay in
the exact parallel direction for every hole,
or one hole may spray in 2 different directions.
plus you need something to plug up the end.
as DIY projects go, this does not seem worth it.
Yes, I would use it if a clear spray bar matters to you. It will need to be cleaned more because you can see all of the build up but I see nothing wrong with it. All of spypet's points are right but if you want a clear look then All you need is a drill and a way of plugging the end.
I made one from 1/2" acrylic or polycarbonate pipe that I found some time ago. I used hot nail to make holes, but then carefully removed excess material and enlarge holes until I was happy with it. I plugged one end with a capped piece of bubble-bar and connected the other to the powerhead. It didn't cost me a penny, but that's because I had spare parts.