We have several teardown tables.
Kind of depends on how many and what kind of transmissions you will be doing.
We have one of the little red ones like are linked above, but the drawer or pan or whatever that holds fluid is long gone, there is now a 5 gallon bucket there.
Its a little on the small side for its intended purpose.
For a rear wheel drive trans its not too bad if you have a solvent tank handy to toss the pan/tail housing in and clean them right away, then pull it down to the case and put the case in the parts washer/tank and then tear the drums apart in the space where the case was.
Piling things up higher is also an option, but then you end up handling parts more often than necessary. Fine at home, not so good in a shop.
Bigger front wheel drives and say 3 shaft 5 speed Hondas or an Allison are quite a bit more crowded. Can still wash parts as you pull and set on drain area and/or build table, but can sometimes be an issue if you need to get it torn down all the way so you can order parts in time for a supplier run.
Speaking of suppliers, check with your local trans parts place, sometimes they have tables on sale.
6' is a lot handier size, roomy enough to teardown pretty much any passenger vehicle trans, and keep tools and what not on.
Somewhere online I found 6' ones for $695 delivered, I think they also had 8' for $795, and a 10' for $1000.
Here is the 10' one, I think the same company has the 6 and 8 footers also. No clue about why not available until oct 16.
http://www.ebay.com/itm/T-0177-A-10...ssion-Engine-Sloping-Work-Table-/280766507224
These are about the cheapest functional looking ones I've seen.
I was thinking about stopping by the local steel place, one of them anyway, its huge and they have all kinds of metalworking machinery.
If you could get a 4x8 sheet and have them bend the trough along one edge and a lip down opposite, it would be fairly easy to weld on catch rails and make a base out of angle iron or whatever one could find. If they have a cut off might be able to get a break on price, would depend on how much they want for it to determine if its worth the effort.
Edit: We don't really need another table or I would have given them a call, or stopped by for a price.
A morgue table would probably be dandy, not sure where you'd get one though. I imagine they would object to someone wheeling one off. Especially loaded.
Another place to look would be used restaurant equipment. Its stainless which is great, fairly heavy duty, often has drains or a sink section you could put a plate over and a bucket under or whatever, and if its beat up pretty bad I imagine you could get it cheap, and after a couple of years of beating on it with transmissions its going to look like that anyway. Another plus is they often have good wheels.
Both of my build benches are old restaurant equipment.