Studio rebuild.

Hey all, A few years ago, I bought a house from a friend. While the house has a nice view, it also had a recording studio (wife was all about the view, I, of course, was all about the studio). He left a lot of his gear behind, and has finally moved it out. So it's time to rebuild the studio properly. First up, the control room, since I mostly mix. Details about the build: - The room is 13' 5" x 13' 3'x 8' (LxWxH). - Since it's been a recording studio for over 10 years, the neighbors are ok with what little sound leaks. So I'm mostly concerned with getting it acoustically right. - Budget? I've got more time than money and access to another place to mix, so I can afford to spread this out and am not in a rush. I want to get it right. - The control room is located above and to the side of the live room in what I suppose is called a "utility room". This is a smallish room, that is underneath the kitchen and part of the dining room in the house, sits on solid ground. You descend stairs to get to the live room, which used to be a garage. - The control room shares space with the laundry, HVAC and Water Heater. - The ceiling has a weird jut as you'll note in the picts below. Here are some pictures (cell phone picts...sorry I missed the digital camera revolution) of the space (with gear). - The area with the water heater and HVAC will probably be walled off to create a machine room to house my 24 track and Pro Tools interfaces. 360 view of the room as it stands: (some model picts and current skp file of the studio in the next post since I'm over the limit). Questions: 1. See that door in the third picture? That leads to the outside and is really confusing any layouts I've tried. It's the door where you can load in and out big items (e.g. my beloved Ampex MM1200). I'd really rather not block it off. Since it's in the corner of the room, it's really messing with any layouts I've tried. Ideas? Can I fashion a bass trap that is on hinges that I could move out of the way should I need access to the door? (I've done some searching on the forums on this and the results were mixed, Bass traps need a tight seal, or not...they just need to be filled with rockwool, etc). 2) My idea of building a machine room. I envision creating one wall in front of the water heater and Heating unit, then another flush with the laundry room. I'm sorta concerned with heat/fire issues, by containing the heater and water heater in a confined space. Is this realistic? See the picts in my next for for details. 3) One idea I had was to turn the under the staircase space into a big ol' bass trap. If I walled off the area under the stairs, stuffed it full of bass trap material and just put some fabric over any areas exposed. Would that function as a bass trap? I guess the real question is, will a bass trap work if takes up a portion of a wall, instead of the entire wall. 4) lastly, and this is a long shot question...to REALLY do this right I would build the control room under the house at the garage level, I would have to excavate under the rest of the house and extend the "garage" and build the control room. The pluses would be a higher ceiling and a custom space...the downside I'd have to dig out dirt and lay a new concrete foundation and retaining walls. Has anyone done this? If so, what am I looking at in terms of cost. What it cost you is fine, I can covert currency and it doesn't have to be recent, I just want a ballpark. Thanks all!

sketchup jpg of now: sketchup jpg of Machine Room: skp file of the bare control room: