Jim O'Sullivan Photography | light cart
I have a Stanley Fatmax Tool box that I use to house ALL my lighting equipment & accessories. It fits my two Alien bees in the bottom with about 100' of extension cords, my transmitters, batteries, Vagabond mini, diffusers for my softboxes, etc. Literally....ALL my lighting gear.
& it's cheap too! $80-$100.
So, using 1"-something PVC piping, aluminum bars, & some U-bolts......
I took the tripod legs off one of my tripods, so, with the tripod legs off, it’s virtually a monopod now.  Slip that bad boy right into the tube on the left.  Look close at the bottom of that left tube & you'll see a bolt going through the base of it.  This keeps the lightstand from falling out ;)
That pipe on the right....is held on by Gaffer's tape.  It's placed in between the ends of the U-bolt, and the gaffer's tape just holds it in place.  Placing it inbetween those ends keeps it from rocking side-to-side.  This is just used to hold my Apollo Orb umbrella...it's not intended to hold the lightstand at all.
Attach the strobe head & beauty dish, & rock & roll! I have the vagabond mini in the bottom drawer, & the extension cord just runs up & out of the drawer.
I also have an Apollo Orb modifer....
& as you can see...i can still open the toolbox w/ the light on there! This also provides more of a counter weight whenever I have to extend the light 10-feet or so.