Oberon makes a box that comes with aluminum mounting "wings" that can be used to bolt directly to the floor.
http://www.oberonwireless.com/WebDocs/Model1020-PS_Spec_Sheet.pdf
**BE SURE TO ORDER THE 1024-PS NOT THE 1020-PS ** The 1024-PS comes with a taller cover that is necessary to accomodate the AP+mount kit+backplate. The 1020-PS is not deep enough.
It fits the AP225 almost exactly. We have done thermal analysis on it and in an indoor temperature controlled environment you can run with no issue.
I recommend using the AP-220-MNT-W1 mount kit to attach the AP to the back plate. Leaves lots of space for cable routing inside the box.
Here is a pic with an AP-224.

And here is a pic showing the -W1 mount on the back plate. (not screwed in yet).
