First the bad news: "Fast lens" and "large format" rarely go together. But remember that a large format camera gives you movements...most people think of movements as a way to move the plane of sharp focus in order to get more of the image in focus. Here's the good news: There's no reason you can't do just the opposite...move the plane of sharp focus so that only a very limited area of the image is sharp. The aperture of the lens will still have an effect, but with careful planning you can restrict the sharp parts of an image to a very limited section of the picture. (If you have an understanding of view camera movements, then you know that tilting the font standard down lays the plane of sharp focus down, thus brining the ground in front of you and the mountains far away into focus. Now, imagine what would happen if you tilted the standard the other way.) Although there's a lot more information available for using movements to get an image that's sharp thoughout, it really doesn't take much effort to mentally reverse the process to get the plane where it will give you the shallow depth of field that you want.
As for money, remember the old saying: Save your money for the lenses. $3000 is a significant chunk of change, but if you're going to go with an Arca Swiss that you'll be happy to use out of the studio, then $3000 is probably going to get you your camera and not much else. If you're looking to buy new, very wide-angle lenses for the camera, then $3000 isn't going to go too far there either. (Schneider Super-Angulon XL 38mm f/5.6, with the center filter that you
will want, comes to almost $1900 at B&H.) So if you looking for a brand new, top-of-the-line, extreme wide angle (remember, the camera, lens board, lens, and even the cable release are special for wide angle) system, then $3,000 won't even get you in the door. Sadly, the type of equipment that you're looking at is extremely specialized, and therefore isn't available often on the used market. (The widest lens that KEH has listed right now is 65mm.)
Now, all of this looks like bad news, but remember that you can always adjust your expectations to fit your budget. (My first 8x10 system, including 3 lenses, a camera, and 6 film holders, cost me less than $750.) First, determine if you really need new equipment. If not, then there are plenty of bargains to be had in used LF equipment. This is especially true if you're willing to use a monorail in the field. Somthing like an old Cambo SC (that can be broken down into two standards, the bellows, and the rail) can work in the field, and although it will take longer to set it up, it will cost you 10% of what a new Arca Swiss will. Remember that if you want brand-new top-of-the-line lenses, you're going to have to save a lot of money on the camera. Can you live with less extreme lenses? KEH has 65mm lenses listed in the $6-700 range. You can get Chinese-made 6x12 backs for $300. They're not the most elegant things in the world, but they do the job quite nicely.
Here's the bottom line: For a new 4x5 camera, you're going to pay anywhere from around $600 up to any amount you wish to pay. $600 will buy you a Tachihara (a nice camera, very light, but with a spring back), or a Shen-Hao (my personal camera with which I'm very happy, but about which others have expressed reservations). That's pretty much the cheap end of new 4x5 equipment that's designed for field use, and they're both wooden cameras. For another $60 you can get a Toyo-View 45CF, but it has no back movements. If you want equipment that's in the Arca Swiss category, your $3000 will pretty much pay for your camera and nothing else.
Lenses, especially wide-angle lenses, are not inexpensive. $3000 will get you a brand new extreme wide-angle lens with the appropriate accessories and a brand new normal lens (normal for 6x9, that is), if you're lucky.
In used equipment, you'll have much greater luck finding lenses that will fit into your budget. Cameras as well. Given the quality of the equipment with which you'd like to work, I'd highly recommend contacting two dealers to discuss what you want to do and what you'd like to spend. You can contact Midwest Photo Exchange (ask for Jim) and Badger Graphics. Their web sites are
www.mpex.com and
www.badgergraphic.com. They both handle a lot of large format equipment, and will likely be able to steer you in the direction of a useable system. Jim at Midwest handles a lot of used LF gear, and I've always found him to be an absolute joy to work with. I've also had nothing but good experiences with Badger Graphics. Both dealers have made me feel over the years that they're interested in making me happy so that I'll come back again, rather than trying to sell me the most expensive thing they can for the quick buck. You can email both companies and explain your situation and budget...they'll be able to point you in the appropriate direction based on their wide knowledge of equipment and their inventories.
Large format is very addictive, and I've built up both my 4x5 and 8x10 systems inexpensively over the years. But I started with much more "average" needs, and was able to buy in cheaply and then pick out the bargains for the more unusual things when they came along.
I wish I could tell you how to get the system you want for $3000, but I think that you'll struggle if your requirements are new, top-of-the-line, and extreme wide-angle. The equipment is out there, but at very high prices.
I wish you the best. Be well.
Dave