TOPIC:

Does anyone make a modern version of the portable toolkit for a kz1000? Like with wrenches in the right sizes (two sizes per wrench), pliers, etc, I want an onboard toolkit but don't want to pay vintage or OEM prices.

I don't think so, but you can easily make up your own at whatever price point you feel comfortable at.

I would get a Kawasaki tool kit off of eb or at a motorcycle salvage yard. You can probably get one for about $25 that has most of the tools you need. There are going to be a thousand or more listed, so search by US only & sort by price.
search = Kawasaki tool kit. other search terms. Concours. Vulcan. Ninja. ZX600. EX500. etc etc etc

Tool bag. The ZG1000 Concours tool bag has the same part number as the KZ1000. It was used on many other models & will probably fit the tool case best. The KZ650 has a different part number, but it's similar in size & was also used on many models.
A Kawasaki pouch might fit the tool case better than aftermarket.