Up until Kubuntu Lynx (April 2012 Long-term-support release), or maybe Pangolin (April 2014 LTS), before the switch to KDE5/Plasma, there was a theme called "Redmond" that made the desktop look like a classic WindowsNT (which disappeared in Windows 8, but that's a complaint for another forum ).

I really miss that theme. I know about the windows widget style, but that was *in addition* to the theme; the theme made the window borders and decorations look like NT. It also really amused the occasional new tech support person, who would be shocked that I was using Windows

Unfortunately, I'm a kernel/security/networking guy, and this is protocol layers above what I'm comfortable working with. What would be the community-appropriate way of encouraging someone to develop this for the current release?

Cheers,

/ji

I don't know about the possibility of porting that exact theme over (probably shouldn't be too hard as it's probably a very simple theme, just a matter of someone willing to take the time to do it), but doing some googling turned up a relatively recent "Redmond" theme collection: https://store.kde.org/p/1109994 which links to http://b00merang.weebly.com/ which advertises free themes for Linux, including various themes for emulating the look and feel of various OSs and desktops.
It looks like they use the QtCurve style engine to work with both GTK and Qt apps. (My first reaction to this request was to check out QtCurve and use that to recreate the Redmond look-and-feel (it provides a configuration GUI that you can use to tweak various aspects of the style. My second reaction was to check to see if there was a QtCurve preset on store.kde.org for it which lead to the above links).

After digging in to the b00merang themes, the reference I saw to qtcurve is erroneous. They only provide Gtk themes.
That said, you can configure the qt theme to use the currently-configured gtk theme and use one of those themes. (the nice thing about qtcurve is that it supports both qt and gtk directly rather than relying on qt's emulation of the gtk theme)

Some more searching through store.kde.org for QtCurve themes, I did find a couple that may be close to what you want (or you might browse through yourself to see if you can find one that suits your fancy): Geek (kind of a pre-win 3.1 theme - mainly simple boxes), Three Point Wanabe (tries to be a win 3.1 look-alike), net theme (another "Classic Windows" look, that's somewhere between the 9x and xp themes), Win2-7 Pack (a collection of themes to emulate various windows styles; though opening it up it looks like it only has the gtk themes, no QtCurve presets, but like the b00merang themes you can just set the qt theme to use the gtk theme).