Personally, in a somewhat unique situation like this, I think one of the goals is going to be using a speaker setup that can move along with the television so that the sound and image are always lined up and coming from the same plane/axis.
Revel has a great option with their LCR8, which is part of the Concerta On-Wall series. The LCR8 is a single, nearly 40" wide speaker that includes the Left, Center, and Right Front speakers all in one, sealed, aluminum cabinet. It's much like a "soundbar", but it's truly just three speakers that happen to share an outer cabinet.
So far as on-wall speakers go, I was quite impressed with the M10 and C10 Revel on-walls, which are part of the same series and use the exact same drivers and tweeters and cabinet design. You can read my impressions of those speakers in
my post here . The LCR8 is basically three of the smaller M8 speakers all put into one cabinet
Figuring out how to mount the LCR8 above or below your television might be a bit of a challenge. But the included mount for the LCR8 allows for some adjustment, so I'm sure that with some planning and a trip to the hardware store, there's a simple enough way to get the wall mount affixed to the same scissor mount as the TV. If all else fails, you could simply use the included table top stand and just sit the LCR8 on top of your entertainment unit.
Now, the LCD8 definitely needs to work with the aid of a subwoofer. I found Revel to be spot on with its recommendation of a 110Hz cross-over to the subwoofer. That's a little higher than normal, but with a good sub placed at the front of the room, the blend is still quite natural and pleasing.
I'd highly recommend a nice, compact, sealed sub like the SVSound SB12-NSD.
Revel only sells through authorized dealers, but you can find the
Concerta speakers for lower prices from "grey market" dealers. I've used DigitalCraze a few times now and I've been satisfied with them. You have to be prepared for the usual "grey market" dealings - ie. phone calls after you've placed the order to inform you that shipping isn't free afterall (even thought the website says it is), or that it will take a few weeks for the item to be available for shipping with the usual options to "upgrade" offered as an alternative. It's definitely a little shady, but so far, all of my dealings have gone through without a problem. The people who've called from Digital Craze have been polite and not pushy. Most importantly, communication with them has always been solid for me. They've kept in touch with emails or phone calls at all stages of the buying process. So you lose any manufacturers warranty and there might be some waiting involved, but they do come through and with a considerably lower price. That said, if you're buying more than one item, you can always haggle with the authorized Revel dealers too
MSRP for the LCR8 is $750. DigitalCraze sells it for $600. You can easily round out a 5.1 system with the M8 on-wall speakers that perfectly match the LCR8, or you could opt for the very good Revel Concerta S12 surround speakers, which you can configure as di-pole, bi-pole, mono-pole or dual mono (literally two speakers in one cabinet), all with the flick of a switch! I really like the S12 since I personally favor diffuse surround speakers. But the little M8 might make more sense, and they're much smaller and very easy to mount on the wall.
You should have plenty of room left in the budget for a great subwoofer. Like I said, I think the SVSound SB12-NSD is the perfect match. Emotiva's subs might also be a good option.
If you buy from DigitalCraze, you could get the
Revel Concerta LCR8 ($600) with a pair of
Revel Concerta M8 for surrounds ($210 each, so $420 for the pair) and actually get DUAL
SVSound SB12-NSD subs ($1150) and still be within your $2000 budget! That's a heck of a good system in your particular setup, let me tell you!
Hope that helps.