So this is an old thread. And likely she has already found her solution... or at least the answer to her question. But as she hasn't posted again, I would like to add some further insight as far as my own research has gone.
Contacting Dr. Domanskis myself, I only asked about 2000cc custom made. And he can get them. He mentioned he can get larger, but I didn't ask how large.
Custom breast implants are not a "made-to-your-design" implant. It's just that they are made on-demand. They just don't keep them in stock. You still can only pick from the sizes and dimensions that they have molds already made for. At least through Dr. Domanskis and his supplier. If someone wants a truly 100% custom implant made, the cost is extremely high as you would have to pay for the mold and manufacturing parts needed for that. Which involved engineers, etc. The cost of designing and building the mold will easily cost a fortune. I don't have any sources, but based on other information in the engineering and manufacturing world, likely 5 digits just to create the new mold. Then you would still have the high cost to make the implant after that.
So at the moment, the best option would be to contact Dr. Domanskis and see what sizes of silicone implants he can get manufactured. The cost will be high, time will be long, and dimensions will be pre-determined based on what molds the company already has for each size. Which could be only 1 variation per size. You have to ask.
I just wanted to make it clear that it's not as simple as asking for an exact width, projection, etc and they custom make it to your specs. That is possible, but at a much much higher cost. And they would still have to offer that service, which they may not.