basement studio questions

I currently operate a mobile recording rig, but I am wanting to create a usable space for mixing and recording select clients in my basement and I am mostly at a loss and need some input from some knowledgable people. The basement is entirely underground (no walkouts) and is partially finished. The walls are cinderblock and the ceiling is finished w/gypsum board. The measurements are 18' x 18' (give or take an inch) with a 7'3" ceiling. The AC/water heater partition will be finished with doubled gypsum and insulated stud walls. The stairs are wood up to the room boundary and then are poured concrete and have a gypsum/stud wall partition. The ducts are exposed and wrapped in insulation. There is a wooden support beam and a metal support beam. My plans are to treat the walls w/ homemade absorbers (entire block surface most likely)along w/some diffusers, and the ceiling w/absorber clouds. The ducts are probably going to be covered and treated hopefully in a non-boxy manner. I am also building several 7' entirely treated gobos for separation/isolation. Isolation from the rest of the house is not a high priority as my wife is also the studio manager. My budget for this makeover is very small (less than $1000). Thanx in advance for any suggestions. Here is a diagram:

Whats the scale of your drawing????

Sorry for that. Each square is 1/2'. Each darker square is 4'. I also failed to mention my equipment. I record to hard disc with a digi002 board and a G4 laptop and a 12u racks worth of equipment (not counting stands of course). I use KRK RP-5 monitors that sit on 1' square stands. Also, most of the work I will be doing here is mixing and pre-production vocal/instrument work (so not many full drumkits). Also (dang!), the floors are poured concrete that I have covered with some of those carpet squares (2 different naps, one more plush than the other).

I am thinking about using the space next to the stairs for an "isolation room" using my 7' gobos as a 4th wall when needed (I plan on adding windows in some of them). The stair wall is gypsum while the other two are cinderblock and will have to be treated (thinking of using insulation and fabric absorbers and attaching directly to the block since the block walls are underground and there are no moisture problems). Am I crazy?