Unless you are laying out big money, you can't get a metal sword that won't be a waste of your money. The lowest quality ones that are worth having are still very expensive.
You are much better off spending money on a really good bokuto. Forget the metal sword and invest a very good quality bokuto that will stand up to training. If you have display issues, you can display the wooden bokuto and jo on a sword stand. That will impress most people as much as a metal sword.
I'm not sure what would qualify as a "really good bokuto". I've only ever bought white oak ones which work great and stand up to lots of use. Spending a whole bunch of money on some rare wood version seems like a waste to me in terms of utility. If you want something nice to look at though, I'm sure there are a million great options.
I'd love to see pictures and hear descriptions of people's really good bokutos. Maybe I've been missing out?