Excellent discussion. A few comments:
Live steam simply means steam driven up the column still through perforated plates to vaporize the wash or mash coming down, the classic column (Coffey) still method. Using jackets of steam or coils to heat, say, a pot still, of course is different.
My reading of 1800's sources for rye whiskey is consistent with what Jeff cites as a mashbill from the source he quotes, 80% rye and the rest barley malt. In the 1860's-era Complete Practical Distiller by F.X. Byrn who was based in Philadelphia, this mash bill is given and I believe a similar one which has a somewhat lesser quantity of rye, perhaps 2/3rds rye and the rest barley malt. Glenn Raudins has reprinted this excellent book, see http://www.raudins.com
Regarding Maryland rye. Some people have suggested it was a fruity style. I believe the Heaven Hill website does, in its comments on rye whiskey. This element of fruitiness may have come from top-fermented mashes. It may have come also (perhaps in later years to emulate this quality), from adding a blending agent. I believe that sherry, say, or prune wine, was used for this purpose - they still are in Canada in some cases for Canadian whisky. I believe some American blended whisky uses them, too. These whiskies could be a blend of straight whiskies to which such an agent was added, or a true blend where part of it was aged or unaged GNS.
I think the Mon Valley style of rye was all-rye or mostly so, straight, not flavoured. In Maryland, I think again different styles were made as mentioned including probably the Mon Valley type. As for molasses, young rye whiskey was sometimes served from barrels (this in Western Pennsylvania) that had held molasses.
Also, all the whiskies mentioned of today (Overholt, Saz, Rittenhouse, etc.) are very good. They generally have (is my understanding) a quantity of rye that does not much exceed 51%. There are also a number of super-aged ryes on the market (Hirsch's, Rittenhouse in one or two iterations, Van Winkle's rye and others) that surely offer a historical taste of old rye whiskey. Overholt may have about 64% rye (this was stated in a 1980's book, World Guide to Whisky, by Michael Jackson). All these are definitely one form of rye whiskey in its historical form. Sam M'Harry in 1809 in Practical Distiller (see Raudins' site again) offers comments on varying combinations of rye and corn including ones that would be the same as or very close to what makes up, WT rye, say, today. He settles on 2/3rds corn and 1/3 rd rye (plus always barley malt) as the best approach for both palate and technical reasons - cows liked the slops better than slops with more rye in it - and indeed this mash became the bourbon norm although less rye generally is used today. M'Harry was a Pennsylvanian, not a Kentuckian, so one can see that different mash bills were used even in different parts of the country.
A rye whiskey I consider old-style in the sense of its high-rye content is High West, which comes from a Utah microdistiller but was sourced from outside distilleries pending issuance of its own production. The one I bought is a combination of 6 year old rye and 16 year old, both straight ryes. It is very good, surprisingly light bodied and relatively delicate, but full of the "peppermint" palate which Jackson said in the 1980's characterized early 1900's ryes. I believe this quality comes from their high rye content - one has 80% rye, the other even more, and one apparently uses some malted rye. The label is a little unclear except to emphasize the very high rye content of the mashes for these ryes.
Now, High West has no additives in it. But if you take a straight rye whiskey made from 80% rye, 20% barley malt, and add a little fruit concentrate or sherry, this would in my opinion, based on reading I have done, reflect one type of Maryland rye whiskey. If you want to taste something like this, pour two fingers of High West and add a very little cream sherry (Almaden's, say). Swirl well to mix. Or, try Forty Creek's Barrel Select, made by a microdistiller in Ontario and fairly widely distributed in the U.S. It is an excellent product which combines corn, rye and barley whiskies separately distilled and aged, and (is my understanding) finished in ex-sherry barrels. This product is very good but if you can envision the same approach using all-rye whiskeys, that would amount to one form historically of Maryland rye. For more information of this type (or again, types) of rye, Jim Bready, referred to on http://www.ellenjaye.com
, wrote an article on Maryland rye in a circa-1990 Maryland Historical Quarterly. A little research should turn it up.
Jeff, that comment you cited about diluting to 80 proof for re-distilling in the doubler is interesting. That could not be done today for straight rye as you know because clearly the first run was over 160 proof.