A timely question as I've just been thinking about the same issue and have a potential solution in mind.
I've just bought a bag for my camera tripod and despite noting the dimensions, when it arrived it's much bigger than I thought. I could probably get 4 tripods in there.
It's usuable for its purpose but it occured to me that I could get another one because its big enough to take the various braces ( corner steadies etc), leveling blocks, water pipes, Nemisis Ultra Wheel Clamp, a few tools and perhaps the toilet cleaner bottles.
It came from Amazon and there are lots of similar types. This one was £13 although I see this morning the price has gone up. I'm still thinking about it but it might just do for me.
Free delivery and returns on eligible orders. Buy Neewer 31″x7″x8″/80x18x20cm Padded Carrying Bag with Strap for Manfrotto, Sirui, Vanguard, Ravelli and Dolica Series Stands and Other Universal Light Stands, Boom Stand and Tripod at Amazon UK.
www.amazon.co.uk