Design Suggestions for Multiple DaqMX Task Streaming App?

Question

I'm working on a LabVIEW application in which I'm streaming high-speed data to disk from multiple PXI devices simultaneously.  Each device has its own DaqMX task, and all tasks stream to the same file.  The PXI device configuration (which devices are in the chassis, which slots they're in, and which channels to read from each device) is determined at runtime.
Does anyone have a suggestion for a design model for this?  To make matters worse, I'd like to be able to specify a channel to monitor its data during the streaming.  I'm thinking the Producer-Consumer model is the basic approach, and I'm at the point where I have an array of DaqMX tasks, one for each device.  I could probably extend that array to be an array of clusters containing:
   1) DAQ Command (e.g. Initialize, Start, Stop, Acquire, etc)
   1) Task ID
   2) Control reference to 2-D array (where each DaqMX read can be stored)
   3) Array of channel names (to allow selection of channel to be monitored
This could be passed as notifier data, to a data collection subVI, but the part I'm struggling with is finding the best way to run X number of tasks in parallel, where X is not known until runtime.
Any suggestions would be appreciated.

Answer 1

Thanks for the input.  With regards to the file format, the decision has been made by my superiors not to use TDMS - unfortunate, but NI hasn't provided the information to write a MatLab file reader, which is a requirement.  So, I've created a custom file format tailored to the needs of my application, but generic enough to be used for other apps. With it, I've been able to stream 8 channels at 800KHz (4 channels each from 2 PXI-6120s) without breaking a sweat.  However, the performance varies greatly depending on which slots the cards are in (but that's a whole different discussion - see the PXI forum for that one).  Once NI solves that one, I'll feel a lot more comfortable.
I have already made reentrant subVIs that can perform a specific DAQ task.  The problem with a for loop is that the VI sits and wait for a start trigger, then acquires the streaming data.  I can't start the next VI because I'm in the first one.  I thought about creating a data collection VI, and this VI would start up to 6 other VIs in parallel, based on how many and which cards were present.  It's a bit messy, because each slot can contain one of two devices, so I'd need to check which type it was before calling it.  I'm thinking I'll have to create the task list and the references to the data in the main GUI loop, and then pass this using a notifier or queue to the data collection loop.