One of those green pickle buckets from the local McDonalds works just fine for a tool caddy...usually cheap as well. Not only can you tote your tools around, it also doubles as a mini wheel barrow, trash can and stool to sit on when your backside gets tired of being on the ground.

I use a wheelbarrow (since I'm always hauling around mulch, dirt or fertiziler, and bought a few gadgets at stores to store my tools in. I found a rack that is used to store magazines on a toilet. IT has a hook taht fits in the wheelbarrow and stays put. I store lysol and stuff like that there. Then I found something else where I can store measuring cups, a pruner, etc. I don't even remember what it's called. I think I found all this stuff at Bed Bath & Beyond. It just took some experimentation.

I'm surprised some enterprising soul hasn't found a storage caddy to go with a wheelbarrow.

Another option might be to get an organizer that goes with a 5 gal bucket.

For long-handled tools such as rakes, hoes, shovels, etc. an old golf bag is pretty handy.

Try looking at aluminum fishing carts. They have a handle, two large wheels and several verticle tubes for holding fishing poles. Made for riding over lose sand, they are easy to pull and hold a ton of stuff. Rake, shovel and other long tools fit in the pole holders. The main body, made to hold a cooler, is good as a wheelbarrow to hold weeds, trimmings or a couple 5 gal pails. I keep a plastic storage crate for smaller hand tools. Great for a 'base of operations' to get a lot of stuff to the garden and helps to organize it all in the shed.

FYI to fatso or anyone else who might be interested:

It seems there is already an enterprising soul who created a wheelbarrow caddy... I saw an article in a gardening magazine for one and checked it out. Sure enough, it's a handy organizer that bolts onto the sides, albeit a bit pricey at about $50. Seems like your wire rack is probably a better (and unique!) setup. Thought I'd share the option anyway.

Here is a link that might be useful: Lola's wheelbarrow caddy