I use Rotalux light modifiers in studio by Elinchrom. They are super-duper. Want strip lights, we've got 'em, but I have 2 20x51" strip lights (EL 26181). They work well, but a bit wide to be true strip lights on occasions.
The other day I was photographing a long, tall model with ebony skin. I wanted to put a strip of light on yer legs and side, but I wanted it thin. The 20" was a bit wide. We have a set of Rotalux 14x35" strip lights in the studio, but alas they were out on location. Drats. What to do you ask? DIY time.
Yep, I simply took a piece of black cloth and doubled it over and clamped it to the strip box. Like that, my 20" strip lights became a 10" strip and I got the effect I wanted. All I needed was a large piece of heavy black fabric that I've had in studio for some time and a few industrial clamps.
Sometimes you don't need to buy all the crazy good equipment, you just need to DIY.