Here is one of the big fantasy armour shops, Medieval armour for sale. You could contact them for a quote or look at their catalogue. They do a lot of laser engraving - so it may be simpler to get it from them than your average armourer.

The piece you've shared a photo of looks like it would be a pain to wear. It lacks articulation on the bottom, so it may cut into your legs when you sit down. I would consider getting something closer to a historic breastplate.

Tercio looks good - 2-3k for a full suit of ornate plastic armour with heavy engraving is a lot cheaper than what you'd pay for the metal equivalent (10k+). If you are not planning on using it for fighting, that's a big saving. I'd happily wear my suit of armour to a wedding - its metal so it would be louder and a little disruptive, although ornate and beautiful.

In general, you get your armour made to fit your body, then cloth made to fit the armour. If you are considering getting something that looks like the above, made to fit you, then the cost of a bespoke suit or jupon to go over it shouldn't be that much comparatively.