Why i ask the question "how much do you want to pay" was to see if you have a grasp of the time involved to build a high quality model such as you ask. Then you bring up that you have been in contact with a few payware companies leads me to think A; you are in for a shock if anyone gives you a price or B; Your very wealthy and want a FS version of your personal GV. Just as a guess myself but lets say you wanted something along the quality that Milton Shupe has produced over the years. I would bet the amount of time Milton puts into a model alone would surprise most FS enthusiasts. If you want a VC and panel along with gauges to go with the model That adds alot of time as well. You will still need everything textured as well and then to even make it flyable a good FDE will need to be made to get it to fly close to actual published figures. Since we are this far in you will need a sound file built and that will take alot of time as well. Then everything has to be put together tested and packaged up and EULA's written. So all in i would guess your looking at a few thousand hours of work to get you your Gulfstream and a small team of developers to bring it to life. So.... How much do you want to spend?