Single Audio Channel

Please forgive me if this makes a complex solution sound simple as that is not my intention and while I'm certain I am not the first to think of this idea, I am curious about its possibility.

We regard to plausibility and implementation on the 9530, what would be the issues with a software audio mixer that would be able to downmix multiple channels into a single one before sending it to the speaker? I understand the phone is only capable of playing a single channel at once and that is - at its root - a hardware issue, but would there be a way with a separate background running application or with a modification of the base OS (or plugin, etc.) to mix this before having to send to the phone's output channel?

I'm sure that RIM has some sort of API or code that would be required for this rather well locked up, but I guess what I'm asking is if based off what we know about the phone would this be feasible?

Thanks.