hello Thomas,
First of all: the enlarged intake is NOT a distinctive feature for the A-7 subtype as has been written over and over again. The discovery of that popular, but erronous misconception, was done by Ron Ferguson who has written a research paper on the He219. There is photographic evidence that enlarged air intakes were also applied (or modified later) on 'early' A-0 subtypes.
Secondly: the air intake you see on the (beautiful!) photo is not related to the engine but the Kärcher heating system. I mixed up these too once
Yes, you have read it well: the A-5 was just a planned production model for which some prototypes were prepared/modified but this subtype never went into any substantial (10 or more) production. It is comparible to the planned B-1. It was never produced but of the D-1 at least 5 aircraft have been built in Wien-Schwechat.
I am certainly not the He219 expert, but I built an extensive database on the He219's, thanks to the much appreciated support from air war reseachers all over the world and many contributors of this board and Peter D. Evans Luftwaffe Experten Message Board (
www.luftwaffe-experten.org). Since March 2011 a new, intensive effort has been made to assemble and process as many primary sources in order to put an end to the many myths and anomalies. Thus, a better insight in the complete He219 production (exceeding the 300!) is just one of the results which will be published in a planned He219 reference work.
All the best, Marcel