So my trusty Sony DSC-H5 camera emitted a horrible crunching sound from inside its lens assembly, spat out several error codes which boiled down to “throw me out”, stopped retracting its lens, and developed a nasty rattle. If I thought dropping $2k on a fancy mirrorless DSLR would improve my photography, I’d do it, but instead I picked up a $60 used DSC-H5 from eBay and continued the mission.
Of course, the new-to-me H5 suffers from the half-press switch failure common to that entire line of Sony cameras; my DSC-H1 repair notes still come in handy for many folks.
I’d preemptively repaired the shutter button + switch in my now-defunct H5, so I dismantled it, extracted the control assembly + shutter button, bulldozed the debris aside, dismantled the new(er) H5, transplanted the parts, reassembled it, and declared victory.
Which left me with a pile of parts that could become an H5, if I could fix the lens assembly, which seemed unlikely. While pondering the futility of human existence, I applied a low-effort repair to the defunct shutter button by scuffing the nicely chromed and absurdly tapered tip of the OEM shutter button’s shaft, then applying a dot of JB Kwik epoxy:

The nice sphere came from hanging downward, with the button sitting atop a short brass tube on the workbench.
Filing the dot’s end flat produced a blunt plunger much larger than the OEM tip:

You can just see the edge of the OEM tip inside the grayish end, which puts the filed flat at the original pin’s length.
I punched a new plastic disk to replace the indented one:

Based on past experience, the new plunger tip will work fine, although, unlike the brass screw repair, the OEM plastic pin can still break and launch the spring-loaded shutter button cap into a nearby bush. Given that I may never actually use the repaired button, I’ll take the risk.
Finding out if the new tip will work may take a while:

I did a bit more disassembly than strictly necessary to replace the shutter button, but not by much; you’d be crazy to pay me to fix your camera, fer shure.
“dropping $2k on a fancy mirrorless DSLR”
What about superzoom with RAW format?
http://www.techradar.com/news/photography-video-capture/cameras/best-bridge-camera-1259503
Whew!
Those seem very close to what I want. When the old DSC-F717 I’ve been using for closeups finally stops working, I’ll start with that list.
Thanks for the pointer!