The quest for a cheap, portable HDMI monitor

Something that I haven’t quite solved in a day of searching:  I’ve been looking for a good, cheap, portable HDMI screen.

I’m looking for such a thing for two, maybe three reasons.  The first is that I’m called to the occasional computer repair task, and it’s always useful to have a functional monitor at hand for diagnostics.

The second thing is I’ve been looking into doing more portable computing, maybe off my car power supply, maybe off a luggable 12V rig.  A portable monitor designed for 12V power would really be ideal.

And third is:  My Raspberry Pi needs a screen to call its own!  Sure, it can have its way with any random 53″ television I happen to walk past, but having a dedicated screen would definitely put it farther ahead on my time-pile.

Rumours of a $100 Chinese wonder all lead back to a not-in-stock.  But hey, for $100 I could really just buy a full desktop display and lug it around.

Thus far, I’m only coming back with partials.  The Pi can output in to RCA composite video, making your typical $40-ish car video screen an option.  Newegg has a third-party seller listing one display for just over that, but the similarly priced Digital Prism ATSC710 looks like it has composite or component in, plus an HDTV tuner.  That’s everything *but* HDMI for my checklist.

Small displays *with* HDMI are another story still.  Something I didn’t know before is that there’s a market for $1000 portable displays as a DSLR accessory.  I guess for the money you get something you can drop on the ground once or twice — handy, but not what I need right now.

There’s another trend I seem to have missed: a plethora of “black box” video recorders, ranging up from $50 or so, designed to look out the windshield and record a 5 or 15 minute loop, typically to an SD card.  Many have HDMI out, so they’ve been popping up in my search results.  It’s interesting to look at, but I don’t think I’m sold on the concept unless there was at least a rear-facing camera too.