Frank,
Ave you ever considered putting up a page on your website describing the lineage of the various electronics you have made - maybe as simple as a table with year and model name/number for amps, pre-amps and DACs? (If you wanted to get fancy later on you could also put in a column describing the major design advances over the previous version. Or how to identify that particular model.)
Some of us lament not keeping the product listings that you so dutifully sent us each year. It would be really nice to have a simple list, especially since we find ourselves your electronics over time. Since there is almost always one or more AVA product on e-Bay or AGon it would probably also help (prospective) buyers and sellers.
Jim
