Wow! Lots of great stuff in the past few hours, everybody. Thanks for the input.
Thanks for putting in all the tedious cryptographical work, especially correlating frequency of rune with frequency of English letter. That was a great theory, but no one had yet put out the effort to prove or disprove it.
Shaft, great thought about "sh" standing for Shael instead of Sol/Shael/Sur+Hel. Same could be said of "th" for Thul (or even Eth and Ith for final-consonant uses), although we may be ascribing way too much linguistic skill to the Blizzard team.
For my part, I went through the quiz questions and answers again for suggestive words and capitalizations, and here is what I found:
Round 1 (Baboon Demon) - No auspicious capitalized terms in either question or answer.
Round 2 (Blunderbore) - No unexpected capitalized terms in description. "Mauler," however, is one of the monsters in the category, which could suggest hammer as the item type.
Round 3 (Pandemonium Fortress) - A number of oddly and not-so-oddly capitalized terms in description: Heaven, Hell, Light, Gates, Burning, and Angel. As I have mentioned before, "Light" could suggest any of Daylight, Starlight, or Lightning off the 1.07 list. "Heaven," of course, could refer to Heaven's Will.
Round 3.5 (Hratli) - No auspicious capitalized terms in either question or answer.
Round 4 (Stained Glass Windows or An Evil Force) - Numerous capitalized terms in the text from which the answer was drawn: Lord, Terror, Stained, Glass, Windows, Mesas, and Hell. "Terror" could suggest the Terror runeword from the 1.07 list.
Round 5 (mage-clan or mages) - I cannot find a definitive passage of text from which this answer may or may not have been drawn from Arreat Summit.
Round 6 (Uileloscadh Mór) - The sentence which contains the answer in the Druid history section of Arreat Summit capitalizes the following words: Barbarians, Steppes, Mt. Arreat, Burning, Hells. Kenny capitalized both Man and Demon in his original question, although neither are capitalized in the source passage. None of these terms coincide with any inactive word from the 1.07 list. The Druid page containing the sentence, however, mentions nature many times (not surprisingly), and the recipe for Nature's Kingdom on the 1.07 list is UmEthUmRal--not terribly different than Uileloscadh Mór.
Round 7 (Drognan) - Drognan's description contains the following unnecessary capitals: Mage and Clan. Perhaps this clue could combine with Round 5 somehow.
Round 8 (Geglash) - As mentioned above, the word "Water" is oddly capitalized in Geglash's description.
Any other conclusions?