Can my attic work as a listening room??

I am contemplating finishing an aready framed attic space in a newly built home (1999) (walk-in entrace off the second floor of my home over the garage space). The collar ties will be moved up to allow an 8ft ceiling at the center of the room but the side walls will slant down to a four foot knee wall making the average ceiling height closer to 6 feet or so. The usable length of the room is 17 feet and the width about 12 feet when finished. I will probably put in a dormer on either side of the roof for light but this will not add much in the way of additional room dimensions. The subfloor is 3/4 " plywood, glued and screw nailed at entire area over garage. Collar ties are 2 x 6 douglas fir 16" OC. There will be a double hung window at one end of the room and the entrance door at the other long end.

I was hoping to put the speakers about 7 feet apart OC, 4 feet off the back short wall with the window and a couch about 7 feet in front of the speakers. With this spacing, the speakers will therefore only be about 2 feet or less off the side walls (4 foot vertical knee wall) with slanting wall attached to the roof rafters. The middle part of the ceiling is at 8 feet and about 6 feet wide. The other option is to put the speakers on the long wall but now the couch is flush against the opposite knee wall to get a listening position at about 7 feet, and reflected sound off the back slanted attic wall may be too big of a problem.

I realize the entire room is not optimal and very small making listening almost near-field but with acoustic treatment, can some of the major problems be resolved to make the space usable for high end audio? I listen to female vocals like Eva Casidy, alot of Jazz and some classical music but hope to expand my CD collection once I purchase the system. I am looking at Wilson Audio Watt Puppy 7 speakers and tube amps. Any help would be greatly appreciated.

Even though it is an expensive colonial home, there is no place where I can put all the audio gear without Marital discord or childrens prying hands. The unfinished basement could be used but I hate artificial lighting an potential for dampness.