Well here's the thing:
the highest number of discrete channels you're going to find in any recording today is 7.1. Any 9 speaker or 11 speaker setup is using processing to "create" new speaker channels out of the existing maximum of 7 discrete channels in the recording.
The "expansion" programs use phase and time information in the existing recording to make their "best guess" as to height and extra width information. It's very similar to how Dolby Pro Logic IIx would take a 5.1 recording and use the phase and time information in the two surround channels to "expand" and create 2 surround back channels for a pseudo-7.1 mix instead of 5.1.
Personally, I find the usefullness of the 8th & 9th "height" or 10th & 11th "width" channels to be extremely dubious. If you have 7 speakers properly placed and calibrated, you already have height information from the surround and surround back channels and you already have width information from the Front L/R and surround channels. Truthfully, the only time you'll notice a difference is if your existing speakers are not placed properly. All of the audio information is already in the recording. The 9-channel and 11-channel programs aren't creating anything new, they're just "steering" some of the existing information into new speakers, exactly the way the DPL IIx would "steer" some of the existing surround speaker information into the surround back speakers.
So if you are just aching to expand your current speaker system, do it by getting a pair of Paradigm ADP surround speakers that match the line of your current Paradigm speakers. Put your new ADP surround speakers in the correct surround position - directly to either side of your seat and about 2-3 feet above seated ear level.
Move your Mini Monitor speakers to the surround back positions at the back of the room, also about 2-3 feet above seated ear level.
With the diffuse ADP surround speaker properly positioned and the Mini Monitors as your surround back speakers - also properly positioned - you'll aleady have the intended height and width sounds - no 8th, 9th, 10th or 11th speakers necessary!
If you just can't stand the idea of not using those 8th, 9th, 10th & 11th speaker connections, go ahead and get some Paradigm Atom monitors for the height channels - pretty much nothing comes out of those channels anyway, so you might as well make them the smallest, cheapest matching speakers available.
Ideally, the width channels should match your Front L/R speakers, your Mini Monitors should be a pretty good sonic match to your towers, so long as you bass manage them correctly. You could use Atom monitors for the surround back channels if you go this route to keep the cost down.
But honestly, I see no good reason to bother with the artificially created height or width channels. Just get some ADP speakers for the surrounds, move the Mini Monitors to the surround back spots, place all of the speakers correctly, and you'll be enjoying your 7.1 discrete soundtracks the way they were meant to be heard, and not how some DSP program "guesses" where some of that phase and time alignment information can be spread around to new, unnecessary speakers.
