Now, we have movement trays. There are various ways to make them. I prefer the GW method because it is really easy and very cheap. For $9 you get enough trays for 200 small based infantry and 128 large based infantry models. They make it easy to keep the models lined up and wheeling nicely.
The key with these movement trays is to map out how you want them from the beginning. With my beastmen, I knew I wanted at least two big Gor hordes, so 4 ranks deep by 10 ranks wide. I put together two sections that would hold 40 gors in it and glued them together.
Then you put corners and sides on. That part is pretty simple. I wouldn't actually recommend corners and sides on the back. Sometimes a unit is a little large by a few models (because of characters, for instance) so you have to have a few models trailing off the back.
See the first instance of a movement tray:
|A 30 man small base unit tray with sides and corners.|
|Flipped over, we can see the larger infantry base size of the unit tray|
|A 4 x 10 large base tray. This fits my entire Gor horde.|
You can go a lot further with the actual basing and flocking... see some examples: