OK, after quite some time of quiescence on this project, some bugs were brought to my attention.

First, rather embarrassingly, a character generator bug resulted in to graphics characters being incorrectly rendered.  [harald-w-fischer] had pointed this out over a year ago, but due to ever-present-and-multitudinous weirdness in this platform, I did not receive notification of his posting until recently, when [Mikael ?. Bonnier] observed similar consequences.  Thank you guys, and apologies for not having corrected it until now.  (And extra special thanks to Harald for digging into the code to effect the fix himself!)  I also reflected this fix into the 'wide character' font, and along the way noticed that character 0x7f didn't look quite right, and fixed that too.

Second, and perhaps more embarrassingly, Mikael discovered that saving to cassette tapes did not function.  I guess I have never actually tried to save to a cassette, because Lo! and Behold! it is true it did not work.  This ultimately was due to a trivial logic error of inversion:  the cassette write routine is meant to verify that a cassette is selected, before writing data.  In fact, the opposite was done, and if a cassette was selected, it would abort writing.  Heaven's knows what would have happened if you tried to save with no cassette selected (Heavens does know:  crashy-crashy).  Anyway, that logic error is corrected.

So those two bugs are fixed, and I have updated the 'files' section with images I have tested.  I left previous image in place just in case this for some reason doesn't work, but I'm quite confident of the fixes.

Lastly, Harald has a rare-ish piece of hardware:  a modded Model I with the HRG1B board.  There were a very few 'high resolution' boards for the Model I back in the day, but most were farcically unusable.  The HRG1B seems to me to be the only sensible implementation, which is a dot addressable pixel array (of the impressive 384x192 resolution!) that overlays the native resolution.  I can only guess as to how much such a thing cost back then.  Anyway, I've never found any documentation on such, much less software, but Harald has a vintage copy of the graphics kernel driver and some sample programs, so I'm now eager to implement that support.  I haven't spent much time on the software, but a cursory disassembly of the kernel and a glance at the BASIC source looks like might be some interesting things are in there!