Home Depot sells 'em.
Try this: (sorry for the huge pic!)
I have two of these for my iguana. One outside on the screened in porch and one in the living room (my wife loves it -not) where he sleeps at night.
Leave the top shelf off. It's too high to easily pick the iguana up from. Use the vertical "poles" to mount your heating elements or UVB lights.
I use a plastic coated wire closet shelf as a ramp or ladder for the lizard to climb up.
few older pics -
okay VERY old photo - that palm tree in front of the shed is as tall as the shed now!
This inside one just has the wire shelving "ladder" straight vertical and Mr. Ted climbs it with ease.
yes, there is a sleeping iguana under there
An enclosure that isn't enclosed is a shelf!