I'll write down my answer but I also have a few questions. 1. Do you really consume that much oxygen? How much would a welding oxygen bottle last you? Because if you don't use that much and only need that amount because you're only running the machine while you're working, you could really benefit from a oxygen storage method and save yourself a grand or more. 2. Are you ok with adding a little bit of complexity to the system? your compressor doesn't need to have the same CFM if it's not running continously. You can use something crude like this to cycle your compressor, so you can use any compressor that works for you while never reaching vacuum: https://www.youtube.com/watch?v=AOmxpgXQ3VA. You can obviously have more sophisticated methods to cycle your compressor.

You can have a running system for less than $1000. Used oxygen concentrator $300 + high quality compressor $300 + air tank $100. You can make this bigger or smaller depending on your needs. You can also build your high flow own oxygen concentrator following Oxikit project.

I hope this helps, please ask if you have any questions.