Have a look at this gist for my idea about using Decimal values (or converting ints to decimals first) and then dumping in the json so it doesn't have floaty rounding display happening

https://gist.github.com/4536693

Will get back in a few hours with the other stuff I'm looking into.

edit: I am inclined to agree with you on the using integers and correct money handling rather than shitty floats or even decimals. At least in this case, when the value is received and loaded into a Decimal, it will be displayed and loaded completely accurately and not rely on the client correctly implementing rounding, which we cannot assume. As I have previously stated, I think following bitcoind api where possible is best since it makes for the least dicking around when migrating to use armory from bitcoind.

edit2: The option to set integer / decimal / string encoding is a great idea. Don't forget to allow users to set it back to the default for decimal if they desire.

edit3: I had a crack at getting the listtransactions data for the various scenarios you describe (and thus the 'way it works'), however I couldn't get any results. Frustratingly, I got raw transactions to sign (which is the second-last step of many) and then the last step is to broadcast the transaction, but my transactions were always getting rejected. I've got my progress thus far well documented and is definitely repeatable so I might try to work it out later in the week. It's worth asking on the development subform for clarification on the way the listtransactions call works, they will hopefully be able to answer it. Anyway I was creating raw transactions to match your scenarios based off this guide and testnet-in-a-box - https://people.xiph.org/~greg/signdemo.txt