Don't be to quick to write off welding the frame, few people on here started with no experience of welding & learnt fairly quickly. If you buy a second user machine for your build & at the end decide you are never going to weld another thing in your life you can always sell it again & probably get back most if not all you spent on it.
People have done it by bolting the frame together but it's a lot of work drilling & tapping all the holes.
Nothing to be afraid of on this site, no one is going to rip you to shreds just because of your lack of knowledge. You will no doubt get criticism once you start to design a machine but it's constructive criticism aimed at helping to correct mistakes that you may have made or how to improve things. No one will just say that's rubbish & give no reasons for the statement or ideas that would help improve things.
Best of luck with it anyway.