I know that some have kept their igs free roaming without problems. And these are usually adult igs. IMO 22 inches is really too small to be free roaming unless the room has been completely stripped and dedicated to the iguana. You will have the problem of keeping the ig under the UVB light as well as keeping him warm. They just don't have enough body mass to retain heat for very long and being that small there are all sorts of places that he could get into where you cannot find him or retrieve him. My 4 ft+ female will still occassionaly get into hiding places where it is hard to find her. Luckly there is usually a tail tip sticking out to give away her new hiding place.
Lay down on the floor on your side and look around at all the places and things that the ig could get into trouble with. And then there is the pooping problem. Particularly problematic if the room is carpeted. They also seem to like to leave you presents on the bed.
One of the first things you are going to have trouble with is the electronics.
Iguanas are attracted to heat and your computor monitor is going to be very enticing due to the elevation and the warmth it puts out.
And then one day the Ig decides that its time to "go".
There went your monitor!
There is also the possibilty of there being times when keeping the iguana caged is necessary for both parties safety. A breeding season enraged male for instance. You have to be prepared for all circumstances.
