That's an interesting question, to say the least :)
Bulgarian cuisine is quite varied and one cannot say for sure which of the hundred possibilities that could use the generic name "Bulgarian Beef Sandwich" is what Smith was obsessed with.
The Telerik team took your question with enthusiasm and quite at heart.
A quick online search performed by a team member brings some interesting results, such as this one:http://www.yelp.com/biz/EtHdljzW_bFiD10fapLSxQ
Quote: "My friend is fond of the Bulgarian Beef sandwich, though we're not quite sure what exactly is so Bulgarian about it; it's pretty much the same as the Falafel, but with some sauteed beef instead of falafel. Mind you I've never tried it myself, but my friend swears by it and I trust her judgement."
A popular and very tasty beef sandwich in the early 80s could be made with a salami that looks like this:http://en.wikipedia.org/wiki/Lukanka
My guess would be that this is the thing Smith liked, and if you try it you would see why :)
You can order [one variety] of that particular product in the USA from here:
Another Telerik member came out with the suggestion that the "sadwitch" might be in fact another variety made with ground meat and then baked - a very popluar thing to eat in the 80s too, especially in school cafeterias.
Check out this link here:http://www.bgstuff.net/component/option,com_ricettario/func,detail/Itemid,578/id,804/
Some Telerik customers, evangelists and some of our overseas staff have had the chance to visit Bulgaria already and I guess they can share a thing or two about the food they had :)
On a side note, it seems that while Apple engineers were obsessed with Bulgarian food in 1980, Bulgarian IT engineers were equally obsessed with Apple computer. It might be interesting for you that some of the first microcomputers developed and manufactured in Bulgaria in the end of the 70s and early 80s were Apple clones - photos and history provided here:http://www.homecomputer.de/pages/easteurope_bu.htmlhttp://en.wikipedia.org/wiki/Pravetz_series_8
the Telerik team