Re:
I have one (actually, the whole bike), but it's a few hundred km away (it's on long-term loan to a friend), so I can't give you exact dimensions on the bars.
But you can see from the 1995 catalogue:
They are chromed steel;
No bulge in the center (you need to use a shim to fit the 254.mm Kona stem);
The bends in the bar are quite angular (no smooth transition or swoopy curves);
The worst bit is that the grip section is quite short, so they only really give one hand position (compared with the many positions of newer "alt" bars like Jones, On-One, Soma, etc.).
Most modern "alt" bars for MTBs don't have the high rise of the Kona bars. So they give a totally different riding position.
Humpert (from Germany) has a huge range of bars in steel/alu/black/polished. Try to find their online PDF catalogue for dimensions and descriptions.
Example:
https://www.sjscycles.co.uk/handlebars/ ... amp-black/
At the moment, Planet-X in the UK has some lovely Nitto Bosco bars that were designed by Grant Petersen at Rivendale Bikes. They have enough rise, but the bar comes directly back (effectively a 90-degree sweep) like a Dutch Omafiets bike. So still not an exact replica of the Kona bar.
Rivendale link:
https://www.rivbike.com/products/nitto- ... 25-4-16240
Planet-X:
https://www.planetx.co.uk/i/q/HBNIB353/ ... -handlebar
Honestly, the Kona bars are nothing special / unusual (actually they're quite limited compared to the Nitto Bosco, etc., which give multiple hand positions). You just need to find a bar a lot of rise. Similar bars (but often quite narrow) are very common in European bike stores that focus on cheap, upright city bikes, etc.
Hope that helps.
DM
PS: Post pics of the Kona!