They used to make horizontal burning lamps with curved arc tubes.
Yup, I have a couple of these lamps but it seemed like in most cases people just used the standard universal burning MH lamps instead of keeping a separate sku for the wallpacks, shoeboxes, and cobraheads that had horizontal MH lamps. Plus it seems like the ceramic lamps were universal burn but maintained a decent life horizontally.
I never ran mine as they require a special lampholder to ensure correct orientation and I don't have one of those.