Your diagram is good for a start... but there are several glaring defects. First, I concur with others that you might want to consider a "A" studio, a "B" studio, etc, to maximize the number of bands/artists you can work with at one time. This increases your dollar per hour by having simultanious multiple clients. Makes up for days that are dead - and there will be some dead days I can assure you of that.
Another option which I found to be an acceptable cash cow was to have one or more practice rooms. Essentially, a practice room is nothing more than a sound resistant room way in the corner away form your live room/console room, where you toss in all your old amps, your old drumsets, etc. Renting it out for a very reasonable price, allows garage bands who do not have a place to practice, well, practice without annoying neighbors, friends, etc. THe largest of the three studios I've owned had four such rooms, and they were booked solid from when schoo let out until 2am every day, 7 days a week. The other neat thing about practice rooms, is like I said above, you store your old amps and drumkits in there for the renters to practice with. And when you need a certain older amp in the live room, you just to steal it from one of the practice rooms. Think of this as a rentable closet, for bands to practice in. Certainly not the same rates as renting the studio of course, but four such rooms comes darn close. Keeps the lights on. And it's also an opportunity to find new local clients. Bands that practice often in your practice rooms are more likely to record in your studio rather than some guy 20 miles away. They know you, you treat them well, etc.
Another thing to consider, if you are going to have multiple console rooms, is to link them together electronically. One of the studios I had Studio A was analog - neve/otari kinda stuff. Studio B was essentially a mackie 32*8 console with several expanders, wired into more adats than you can shake a stick at (okay, nine). By having patch bay feeds from studio to studio, this enabled us to transfer audio from the adats to the otari's, or vice versa. Also, this saved by having the master stereo recorder in the main studio, and studio B had access to it. Mixing down to stereo for mastering was usually done when the place wasn't rented, so this worked out well for us. We didn't have to purchase two 1/2" stereo decks, just one.
I'd also recommend having more than one vocal booth. If you have two studios within your structure, have two vocal booths. Have them configured between the console rooms so either console room can use both booths. THis too will save you real estate. You can "decide" that booth A goes with studio A and so forth, but by having the cabling available you can "shuffle" both booths to studio A for a larger multi-singer project. Same for your live rooms. Make one gloriously large and warm, and the other a bit smaller, you can use it for smaller groups of artists, maybe a drum room, etc, but by wiring them together via patch bays, you can use anything any old way as your clients require. You can also change your rates if you wish accordingly.
Studio A is $75 an hour, Studio B is $65 an hour, and the whole darn place is say, $85 an hour. Or whatever rates you end up w[ith, but you get the idea.
And I'll agree with Rick that with all prices of recording gear becoming significantly less costly than it was 20 years ago, and with more 'stuff" too, you'll find that the demand for larger studios are going away, slowly. Maybe not completely, there is always a need for a larger, acoustically pleasing facility, but we're in a recording revolution. Just look at Eiffel65... their album was recorded on a computer (mac, I think) with a fancy pre-amp and a nice microphone. The rest of the recording process was VST plug ins and such. That "studio" is a vocal booth and a computer. This will be your competition, especially starting out. Guys with $500 mixers and $200 recorders thinking they're top dog. And a few of them are. A lot of rap albums (and I hate rap too, sorry had to throw that in there) are recording in home studios. Some are recording in disgusting, acoustically embarrassing facilities too. Yet... it sells.
As far as taxes go... you need to learn to negotiate my friend. A few years back I was seriously working to embark on the same thing you're considering, and the building was bought out of mortgage foreclosure for a song. I started the design, and was going to contract it out to John Sayers (
www.johnlsayers.com) to do the real design, and project manage the implementation. For quite a few pretty pennies, but it was going to be worth it. Anyway, the negotiation part is this... I approached the town the building was located in, and expressed "my strong desire to become a participating employer in the town's community". In exchange for promising to hire local where possible, and support at least one youth group of some kind (boy scouts, girl scouts, brownies, big brother/big sister, something along those lines), the town was willing to FORGIVE PROPERTY TAXES FOR FIVE YEARS.
So, I figured the worse case is $2K a year to boy scouts, and I save $20K in taxes? Sign my ass up! The main reason why this worked is the building I bought is in an area of town they wanted to revigorate. No, no burned out buildings or rows of crack whores, certainly nothing that bad... but the economy emptied a lot of the buildings, so the town was being aggressive in the area filling up with legitimate businesses, to AVOID the crack whore problem down the road. Smart thinking on their part...
Turned out the mortage title company screwed up so bad I ended up not owning the building... but negotiate with the town. Emphasize your desire to help build the community. Don't just buy a town hall booster and slap it on the window, get involved. Small towns like that crap. And its cheap as compared to what you get out of it - less or no taxes for a period of time.