Weld or solder a 4" Triclamp port on the bottom of a Sanke. Turn it upside down with the 4" port on the top and the 2 inch on the bottom. Equip with chiller coils, air locks, racking tubes, etc. as necessary.
The good thing about Sankes is that they are totally airtight and they handle pressure. ANd they are cheap. They aren't a conical, but it is very easy to rack from one to another if you want to use one as a bright tank. Beer needs to stay on yeast for a while anyway. If you use CO2 to push the beer, there is no oxidation.
I can fit my arm though a 4" triclamp ferrule to clean the inside of the keg. It is about the same size as the opening on a corny keg. I ferment with fruit, so getting access is necessary.
Not to argue with anyone but My view on cheap vs value here..
A 14 gallon chapman stainless fermenter works the same way as a brewtech brewbucket only brewtech doesnt make them that size... instead they sell a 14 gallon conical for $525.00 with shipping... the 14 gallon chapman is $200.00 with shipping so... on ebay the most expensive items that come up when you search stainless fermenter are the brewtech options so they are not cheap unless you compare them to the american made options like spikes conicals (made by the same guys in toledo that make the blichman conical) The american made spike conical is only $50 more than the chinese brewtech ones so I'm not sure how the savings are being passed on since the brewtech ones cost much less to make in china? I dont see the value? brewtech and spike both have great customer service and a warranty isnt something you should need for a steel tank on a stand anyway.
The "cheap" chapman fermenters are made of 201 stainless like most other kitchen ware ... Its fine for home brewing and even stronger than 304 unless you expose it to harsh caustic commercial brewery cleaners which they dont sell to the public anyway... these cleaners are the main reason for 304 stainless in breweries.
There is another chinese conical sometimes sold on ebay by american home brewer... Its a 12.5g 304 stainless one with a butterfly dump valve. after using it twice now I can say it works very well and the lid seals great without damaging seals. (it even comes with an extra seal). They sell for between $300 and $350 with shipping usually and to me are the best value for the best price.
The ones sold by moonshine distillers are stout clones and are close to the stout quality but not quite there..(unless they changed them they had rougher edges and black plastic cars on all ends vs polished welded endcaps and no rough edges on the stout.
The stout 12.5 conical is a bit better on build quality and refinements but its an extra $100.... Then the brewtech comes in at even yet another $100 more...