Ok, had an evening's pleasant trawl thru the net sources. AchtungPanzer is the most concise, and yes there IS a description of the various mid 30s development model, but the one talked about above , the possible Rheinmetall turret development model? Nope, theres a VERY good description of it, in comparison with a picture of the Krupp version, and this is definitely NOT it.
One possibility removed.
Wondered at the wording of something on the A-P site, so started looking at the munitionsschlepper conversions..... hmmm, back to that in a minute.
Guys, check out the driving pinion at the front of the trackwork; AND the track segments themselves; now compare them with PI Ausf A items.... THIS tank has been greatly upgeared, there as a LOT more teeth on the front sprocket AND the track segments are each individually smaller. An attempt to get more power out of the Ausf A hull, maybe? THAT was the first thing I noticed about the picture, my attention brought to it by Herr Doktor's comment that it used Ausf A running gear.
Now, Ive had a look at a LOT of PI pics tonight, and ONE thing here has caught my attention also, reinforced by pics ive looked at of the command AND munitionsschlepper conversions. Look at the box-section superstructure; THIS conversion goes RIGHT down to hull level! Even the schlepper boxcar conversion was neither as big or as square a conversion as THIS! Now, note the position of the driver's shutter....it has been cut out of the original hullplate and moved UP AND towards the side. Quite a move. Now, the THREE-man cmmand tanks didnt even have this moved!!! AND that superstructure STARTS a lot further forward than any of the tank versions....
Do you know what I think we're looking at? Given the box-section and where its welded into the original hull - A conversion of a Sturmpanzer I Bison! Its the ONLY PI that could have the upper hull shaped like this; AND it would have to have been built like this in a factory, NOT a depot, not for a hull configuration change like that. I've looked at the training tank versions - all the records only list the opentopped training school tanks that look nothing like this.
But THEN - theres one road wheel too few for it to be a Bison hull.....!
Suddenly - i saw a drawing on the A-P site of the Ausf C....and its upper hullwork starts this far forward AND is straight-facing from right to left, not tapered up from the main hull to the turret deck...
SO what we have here becomes more and more impossible. Its either an Ausf C riding on Ausf A trackwork - can this be done??? Or its a Bison conversion, a flat plate across the once-open gun deck to carry the turret.
But its not a factory piece. IF it was we'd have heard a LOT more about it than this, i have NO doubt on that.