Yeah, that's certainly an interesting idea. That way it would also be included in the actual file (in comments) and available to other applications as well. Textastic could display a list of TODO items.

That reminds me of this idea: http://feedback.textasticapp.com/feedback/7796-show-a-list-of-functionsclass-methods/

The scratchpad, which is only available in Textastic, could be an additional/separate feature

I already store information like last cursor position and custom syntax definition setting for each file in the upcoming 1.1 update of Textastic. It should be relatively easy to add a scratchpad feature. I might add an auto-resizing textfield in the file info popover. People could use this for whatever they want to note about the file.

The only downside I see is this: it wouldn't be copied over when copying the file to another app or computer or if you send it via email.

Implementing option 1) would be a whole lot easier if the Dropbox API supported sync out of the box.

Is anyone aware of an existing sync implementation for the Dropbox iOS API with source code available?

I just had a look at Terra Web Browser. Seems like they use a mixture of 4.2 and the 4.1 SDK:

DTCompiler: "4.2"
DTPlatformVersion:"4.1 GM"
DTSDKName: "iphoneos4.1"
MinimumOSVersion: "3.2"

Well, I'll rather play it safe instead of having Apple reject the app.

Well, as long as this is in beta I can't submit iPad apps compiled with the 4.2 SDK but I have to use the 3.2 SDK.

But I tested version 1.1 with 4.2 beta 3 and it's working like a charm. Of course I'll be sure to submit an update as soon as Apple allows this.

That would be a pretty cool feature!

I think I found the problem. It should be fixed in the next update.