Bookshelf speakers with very flexible placement


I'm looking for recommendations on a bookshelf speaker, and have some particular parameters which might mean I'm looking for something impossible. The rooms size is 15 feet by 31 feet and the ceiling are 14 feet high. The room is very reflective, hardwood floors and all straight walls. Though at times there is a possibility of a room divider cutting the space in about half. Also, some room treatments will be added on walls and floors. I am looking for something that I can get a full surround set, though it won't be used in 5.1 all the time. probably about 50/50. 

What I'm looking for:
-Flexible placement is really important. I don't want something really fussy about where it is. They may end up being really close to the walls, they may end being further away. Speakers that only have a really narrow window of where they sound good won't work here. 
-sort of related to above, but good imaging with a generous sweet spot. 
-though looking for enough power to fill this larger space, I'm not looking for blow out volumes. Will generally be used at medium levels, and not for high explosion level stuff like Transformers. More interested in superb detail, and nuance than LOUDNESS. 
-Not too hard to drive. this will be driven with a home theatre receiver. nothing super fancy, maybe a Denon or NAD or something pretty basic. (i don't actually have a receiver yet, and prioritizing speakers as I feel like those are more important).
-simple, neutral design: comes in black, has a grill option, not weird shaped, just a box. 
-price point... Not much more than $3-4000 for 5 speakers. Though happy to spend less. 

I'm looking at this for a project at work. At home i don't have a 5.1 setup so this is new territory to me. At home I use Totem Arros which I like a lot, so am sort of interested in something like the Mite or Dreamcatcher, but not sure how those compare to the Arro. 

Thanks for the tips!

So my first gut response would be to address your room itself and not the system components just yet.  At 15' x 31' and a 14' ceiling height with little or no bass traps, no carpet or upholstery, no drapes, etc, this is going to be a challenge to say the least.  If it were my project, I would work on the room first. I had a similar situation at home although not quite as extreme.  First floor family room on a slab with thin carpeting to start. . I added upholstered furniture, a large thick drape covering the oversized sliding glass door and welcomed my wife to hang wet washed clothes on a portable rack instead of placing them in the dryer.  Now I had a fighting chance.  Over time, built my surround sound audio system with TWO powered B&W sub-woofers spaced strategically apart in the room, a new Rotel multi-channel amp (120 watts/channel/all channels driven into 8 ohms) and B&W/Monitor Audio speakers, Integra processor, NAD CD player.  Fabulous performance. 

So up front you may want to focus on buying two powered sub-woofers to overcome the reflective "live" environment in your large space and place them apart for more uniform room loading.  You can stick with NAD, Denon, Marantz, etc for your components and then for loudspeakers, I would consider Monitor Audio and B&W.  Just my input.  All the best !!