Sorry for the late reply, if you use a vertically oriented 4' enclosure with pegboard on the lower 3' you will probably find that the lower 2.5' will be close to room ambient. This will definitly be the case if you have a glass front.
Personally, I would go with a 1' strip of pegboard between the 1' and 2' mark from the floor (i.e. 1' solid on the bottom, 2' solid on top). I would then use 3 or more horizontal perches at 1.5' off the ground, 2.5' and 3.5' and position the thermostat halfway between the top and bottom perch (with the thermo set to about 28-30).
The only concern I would have with this setup is is the panel overheating, but if they aren't in Loki's enclosure it should be fine.