I would really like to give Bonus-Ressource
Cocoa its own
Improvement.
Currently Lodge (usually for Wood) is used here, too.
I really do not like that very much.
So
1) Anybody have a good name for that Improvement ?
(I am not sure if "Cocoa Plantation" really fits.

)
2) Anybody know
good graphics for that Improvement or would like to create some.

(Anything inside the Preview is already used for other improvements ...)
I installed
TAC 2.02c to understand the problem. Really, our Pioneer has a rather limited variants for Cocoa-bonus tile.
He can
Build Plantation, but we lost Cocoa
(-5 Cocoa).
He can
Build Lodge and we have
+2 Cocoa.

Finally we have a Lodge on Cocoa-bonus tile.
And here we can see the problem reported by Ray: "Lodge (usually for Wood) is used here".
Well, this is very strange for me, too. I expected to see here or "Cocoa Plantation", or at least just an usual "Plantation", but of course not "Lodge".
This error is very easy to fix.
In CIV4ImprovementInfos.xml remove
Code:
<YieldIntegerPair>
<YieldType>YIELD_COCOA</YieldType>
<iValue>2</iValue>
</YieldIntegerPair>
from <Type>IMPROVEMENT_LODGE</Type> section and add the same codes
Code:
<YieldIntegerPair>
<YieldType>YIELD_COCOA</YieldType>
<iValue>2</iValue>
</YieldIntegerPair>
in <Type>IMPROVEMENT_PLANTATION</Type> section. As result you will need to Build Plantition to get full access to Cocoa. Then you will see an usual Plantation building on Cocoa-bonus tile.
Of course, in such variant this action button should be corrected
This is simpliest and fastest way to correct this error. However,
Just to prevent confuison.

(This is not about graphics only.)
In TAC there is only
one Improvement for 3 Yield-Increases:
Lodge -> Yield-Increase
Wood, Yield-Increase
Fur, Yield-Increase
Cocoa
I want to change that to:
Lodge -> Yield-Increase
Wood
Trapper's House -> Yield-Increase
Fur
Cocoa Plantation -> Yield-Increase
Cocoa
My main reason:
It is more atmospheric.
and here I fully agree with Ray. Cocoa requires a special improvement as "Cocoa Plantation".
Moreover, to my opinion
each bonus requires a special improvement with the particular graphics.
I'm very sorry for
off-topic, but let me explain how I organize the improvements in "1492: Global Colonization" mod. Unfortunately, Cocoa improvement is not ready yet, therefore I will use Honey-bonus tile as example.
I have a
Honey-bonus on the tile.
My Pioneer can "
Build Bee Hive" on Honey-bonus tile.
"Bee Hive" is a
1st level improvement. When "Bee Hive"is ready and a unit is working on this tile, the improvement can grow up to "Apiary".
After a number of turns I have "
Apiary" as a
2nd level (final) improvement on Honey-bonus tile.
As you see, I can adjust the goods produced by my improvements: +2 Sugar for Bee Hive and -4 Sugar/+4 Alcohol for "Apiary" (details, see
here and
here)
Here I presented two level improvements. For Cocoa, I guess, only one level improvement is required.
Cocoa-bonus => Cocoa Plantation.
When Cocoa Plantation will be ready in "1492: GC" mod, I will share it for everybody, including of course, "Religion and Revolution" and TAC mods. At the moment I have couple variants of Cocoa Plantation building, however both of them are not ideal for me.