Hmm...
This must be my month for being wrong.
NiLuJe caught me on one just a few days ago that he PM'd me about.
CONFIG_SWAP ?
I certainly don't remember that one.
My only excuse, I was thinking of the mainstream kernel and not considering this is a patched kernel.
As it so happens, I do have a PC sitting here, running a virgin, built-here, 2.6.11 kernel - and it will have its build tree still on it.
So I could (or still can) have checked it out by turning on the second PC sitting to my right.
The built-in command line - -
That is another one that I don't recall 2.6.11 having, but they may have backported it.
The reason for it was so funky options could not be passed to the kernel from the u-boot environment.
Still should not be a problem -
- Its a text string stored in the kernel image.
- It doesn't effect virtual memory or user memory, only the **real** memory the kernel is allowed to use.
And if it used that much, user land would be S.O.L. for having space to run anything. 
Again, that behavior may have been patched by Amazon.
In this case, and in newer firmwares, the reason for a stored command line is the: ip=0 option, which disables the kernel's ability to network boot.
Otherwise, these devices would be too simple to jailbreak.
And that will be hard to text edit in the image, since there are more than a single character in a real ip address.
- - - -
Somebody check me on the above -
I may have set a new record for number of times wrong in a single post.