My set up is as follows -
I have two 6X3 Vision cages, three tegus in each (BTW be careful if you plan to keep more than one together...depending on personality they do fight with seriously BAD results). My Tegus stay in thier cages in the morning, evening and night. I have a fenced in porch where they all spend thier days (I also feed them outside...takes care of the cage feeding response problem).
6X2 is pretty much the bare minimum cage size, and will only work is you let your tegu out to stretch it's legs several hours a day. As far as setting up a room...its a good idea, but it has some drawbacks. Tegus are DESTRUCTIVE, they are large and powerful and LOVE to dig...so anything in the room that could get broken WILL. Also...if it goes in the house (mine are house broken they only go outside) please be advised that tegu excrement SMELLS TERRIBLE (just a quirk of the species I guess)...so keeping that smell contained in one room could be BAD. Moreover - tegus are prone to shedding problems if proper humidity is not maintained, keeping an entire room humid can be challenging...and undesireable.
Assuming you are looking into getting a hatchling...the 60 gal would be good for a few months (you wouldn't actually want a bigger cage than that to start with...a smaller space helps a baby tegu feel more seure). From there I would move it into a room if thats the way you choose to go, a vision enclosure (my personal favorite) or if you are the handy type, save some money and build yourself a custom enclosure. The one saving grace of building tegu enclosures is that tegus don't climb...so there is no need to build the cage very tall...my two cages are only 18 in. tall and house tegus of 3-4 ft just fine.
Also keep in mind tegus, like iguanas and bearded dragons and all those other commonly kept lizards REQUIRE proper UV lighting. My favorite UV light is THE SUN, that's why I put my tegus outside everyday, however with a hatchling that won't be an option unless you build a 'basking enclosure' for it (which would be a good idea BTW), so otherwise you'll need to use special UV bulbs (you are probably familiar with what I'm talking about, right?).
Lets see...thats about it...oh yeah they need places to hide, prefferably a large rubbermaid container with a hole in the side and filled with substrate (tegus like to bury themselves when sleeping). They don't climb but they are intelligent animals (surprisingly intelligent, mine as I said are housebroken, come when called, beg for food, scratch the back door to be let in, actually enjoy human attention, etc.) and appreciate plenty of boxes, logs, and anything they can climb over, look under, explore.
Diet is a much debated issue with tegus, lots of people will tell you that you should feed them rodents exclusively, others will tell you to feed them mostly fruit and vegetables. Fact is, studies show they are largely omnivorous. Personally I just go for variety, everything from fruit, insects, mice, fish, and just about anything they are willing to eat. Do keep in mind tegus are BOTTOMLESS PITS and feeding one (or six...sigh) can get a lot more expensive then you might imagine.
okay...I think that about sums it up...for more info go visit
www.thetegu.com, pretty much the most current info there is about tegus is there. My SN is "elliotjaschief" (myself, my wife, and my alpha tegu), be sure to go check out my picture gallery there too.
Good luck