My good blade carves the casques of men,
My tough lance thrusteth sure,
My strength is as the strength of ten,
Because my heart is pure.
[Alfred, Lord Tennyson]
The Book of War Heroes section has details and pricing on a sample selection of individual knights, barbarians, dragons, and giants; each, of course, tenth level or above.
Now, by "knights" I'm indicating high-level pure fighting-men, and these were actually statted out with an eye towards the AD&D Deities & Demigods Arthurian Legends section (including "Knights Renown" at 10th-level, and "Knight Commanders" at 15th-level, like Arthur himself). With "barbarians" I meant fairly high-level multiclassed fighter/thieves, in the same vein that Gygax statted out Conan at various ages in Dragon Magazine #36, April 1980 (including the "Barbarian Lord", Ftr12/Thf8, as Conan age 25; and the "Barbarian King", Ftr16/Thf12, as Conan at age 30).
In each case, I transformed the characters into my OED minor house modifications to OD&D, and tried to make some reasonable interpolations for magic gear and the like. Because of this, even with very conservative assumptions for magic arms and armor (like just +1 plate and shield for Fighters level 10), most of these characters get converted to Book of War at AH7, i.e., nominally unhittable by any normal men rolling the usual d6 to attack (as is correct in OD&D for any AC lower than -1; and even if you use an "extended natural 20" rule from AD&D or the like, then the chance to hit is still statistically negligible).
But fortunately, this is balanced by the fact that if a lone hero confronts a mass of men, they'll be surrounded, with every edition of D&D giving bonuses for rear attacks in such a situation. Hence the key rule: "acting solo, heroes can be meleed by only 1 normal figure at +1 to hit (due to rear attacks from being surrounded)" [BOW p. 13], which allows normal troops to hit even AH7 solo heroes if they roll a 6. Here's a spreadsheet where I did the analysis in both OD&D and AD&D to see that +1 in BOW was the appropriate bonus in this case (.xls format):
Now, as careful as we might try to be with those statistics, things can still get a bit wonky when you face off hero-against-hero in our reduced BOW mechanic -- especially since heroes can have so many special abilities and varying attacks and armor (the "heroes ignore armor" simplification does break down a bit when confronting other heroes with really out-of-this-world AC values). Therefore I include the suggestion for "Special Combat" on p. 14: when heroes contact other heroes, it might be best to switch back to regular D&D-scale combat and play out that particular engagement at full precision (an idea common to both Swords & Spells and Battlesystem, for example).
I actually don't do that in my own standalone games (particularly with non-expert gamers, it's simplest to just resolve everything with the one BOW mechanic, instead of additionally instructing them in more detailed and time-consuming D&D play). I think that you would especially want to do that in the case when you've got important backstoried PCs and NPCs taking part in the battle. In any event, if you want to run "Special Combat" you'll need detailed statistics in order to run the man-to-man battle. To that end, here's a document specifying stat blocks for each of the human Heroes appearing in Book of War, along with research notes on where they come from (.pdf document; stat blocks within are Open Game Content):
So finally, looking closely at those preceding documents, you'll see another hero type that was included for a while, and then finally cut from the official release. This would be the "Knight Exemplar", representing the world's finest fighting man of 20th level or so -- either Sir Lancelot or Sir Galahad, and none other, per the AD&D Deities & Demigods book.
This is a problematic figure for the game, because his armor winds up converting to AH8, that is, truly unhittable by any normal man (notwithstanding the rear-attacks bonus mentioned above). So the "Knight Exemplar" is a hero who really can smash through a mundane army of practically any size, with standard troops utterly helpless to do anything about it. This presents a real price-balancing dilemma: regardless of cost, this guy wins versus any normal men; and the game is then really dependent on whether the enemy can bring elite-types or opposing heroes (or a dragon or wizard?) into play against him. It seemed pretty likely that this august personality could possibly break the whole game if players had unfettered access to him, which is why he was removed from the final publication.
But here he is presented below, for your consideration, if someone like this comes into play in your battles. The cost is possibly tentative, but it's the best that I could extrapolate. Note that, like other knights, he is given the best possible attack score due to his "Great Cleave" -- ability to hit as many normal men as he can reach (i.e., D&D attack rate as 3+/round, and so score a hit on 1+, as shown in the hero's "Atk" column). Use with caution! (Text between the rules is indicated as Open Game Content, per the OGL.)
Magic sword, lance, horse