one easy and cheap way of keeping them until you decide on the set up, is using
the rubbermade all access storage bins.
they have a semi clear front that flips open and has a lock latch, i would add extra security but for hatchlings , they would be perfect and even up to adults if the big bins are used.
easy to add perches, just add a strip of heat tape in the back, a controler and you're all set.
sealed, rubbermade bins will help keep the humidity in check too.
i've seen a few guys use this with great success, i'm going to set these up for my baby ETBs until i can get xpvc cages for them, i have decide to keep any that is (probably will)
hehehe
otherwise, a rack set up with taller tubes would work but keep in mind GTPs and ETBs need more humidity, so if your rack is made of melamine, it woun't last as long, where as these bins will last for ever.
hope this helps..