A lot of times trees are grown in a collander or strainer NOT to produce a small root system but to get the maximum amount of oxygen to the roots. This in turn allows the tree to thicken much faster then in a normal container.
The Japanese have mastered this technique, something that us Americans haven't figured out yet. We tend to only use them to work with roots, which is only a small part of what can be done with them when you use multiple collanders.
I have found that pond baskets are weak, they get brittle fast and break easy. The best thing I have found for this application is actual strainers you would have in your kitchen for pasta or meats. You can normally pick them up the $1 store.
Still, the best thing so far is the Anderson Flat, you can use them with the "escape method" and still have a very nice, small, fine and flat root pad when done. This is something you won't get with a pond basket.
My 2cents,
Jason