I don't know how compatible it would be to the current 'windowing' renderer that establishes the dialogue/hotspot positions (also, how the unSteamed representations would be,
sans the Premium Graphics elements), but I'd point at the old classic Transport Tycoon, back in the good old days of native-DOS. Among other things, like making use of
whatever RAM was set up in whatever style (no need, like other games, to fine tune EMM386 to give EMS/XMS, or whatever the choices were again, in
exactly the right quantities to run that particular game), it also gave you a Windowed interface where vehicle-tracking 'viewports', report-listings, facility statuses, etc would be generated on demand by the (right-clickish?) user request right next to the subject of your invocation but could be dragged around the screen (the 'desktop' of which was the draggable play area) so you could line the sides/top/bottom with such mini info-portals as you felt like hanging around and could still retain a cleared middle. A breath of fresh air, compared to most of the hard-rendered interfaces/HUDs of the day.
Of course, you needed each inner-window to have a draggable titlebar with close/minimise(?)/maximise(?) controls on them, which took up extra screen real-estate (though they could be overlapped/resized-by-corner-dragspots for some degree of optimality).
Yes, this is now old-hat (though far from universal, even amongst games that really could benefit from it) and even at the time was 'just' copying the best bits out of the three or four major flavours of GUI OS that existed, but it was revolutionary and efficient and aesthetic (unless you went mad with it yourself!) and I make no apology for raising it as my Ur-example, even if someone can point out that it was
not actually the first significant (non-OS) Windowed-GUI Game. For me it is, and I'm assuming you can't turn back time to change my memories. Since then, there's been more the trend to entirely user-configurable Dockable toolbars/etc, perhaps with an undocked 'floating' option as well, and a memory of where they should attach/insert again if previously dismissed and then reinvoked. Again, not enough things use this approach, when they could.
Now, I think it's too late to get Toady to put this in from scratch (assuming it's not already somewhat/wholly in, or forthcoming, but that the current demos just have things appearing where/how Tarn 'likes' them but it's just not how you would prefer), so I'm mostly putting this up as my own thoughts of how to treat this issue. I've probably reinvented the same wheel (e.g. coding hot-configurable Tk/Tcl elements) several times in some of my own toy projects as I tried more to explore the possibilities than actually narrow down on one (portable/reusable) paradigm to present to my audience of one (i.e. me, probably my most vociferous critic, at least by default). It's sort of the reverse of "I don't know much about art, but I know what I like", as I'm not really sure what I like of my own varied 'art'. ...but, anyway, maybe something of what I just said is useful. Probably not inspiring, of course. Never that.
Oh, and if mouse-draggable windows/(re)dockables are a thing, I'd like to put in a request for associated keyboard controls too, some possibly tabbing/meta-key/cursor operations that I can get to like the old faithful Alt-Spacebar+M+cursoring in Windows, etc. Being one of those 'if I don't need to use a mouse, I'll be happily using the keyboard' people.