Lowel (photo/film lighting mftr) makes a large Litebag that is 40" long. I used one for years carrying my light stands on photo shoots till it was too beat up to stitch back together. It held three full size stands and assorted other stuff. Minimal padding so it had a bit of structure but was still lightweight. It isn't cheap but it isn't spendy either.
When mine wore out I replaced it with a Portabrace bag meant for a 40" slider. It's better built and carries more but it weighs and costs more too...
For jobs where small stands are enough I use a Phottix tripod bag I got on sale at B&H. I believe there's a larger version that is 40" long.