〜く＋あります inflections?

Question

In this post, it was verified that indeed the origin of the い-adjective ending 〜かった stems as a fusion of the ending 〜く and the inflection あった of ある (that is, 〜かった comes from 〜くあった). This makes me curious if there are alternate forms of い-adjective inflections that either currently exist or have existed in the past.

To summarize what I had said in that post linked above, I made the following extrapolation.

Modern, plain adjective inflections:

• 高い
• 高かった
• 高くない
• 高くなかった

Historical adjective inflections:

• 高い
• 高くあった
• 高くない
• 高くなくあった

Question 1. Is it also possible, either historically or currently, to use the 〜ます form on the ある portion of the "historical adjective inflections" above?

Formal variations of the above, substituting ある→あります:

• 高い
• 高くありました
• 高くありません
• 高くありませんでした

I know already that 高くありません is possible (at least according to what I've been learning of Japanese on Pimsleur), but I've never heard or seen 高くありました or 高くありませんでした.

Question 2. Furthermore, is it technically possible / grammatical, either currently or historically, to extend this pattern, though perhaps not actually necessary or useful, to say something like 高くある・高くあります instead of 高い・高いです?

Answer 1

Question 1. Is it also possible, either historically or currently, to use the 〜ます form on the ある portion of the "historical adjective inflections" above?

We can find plenty of examples for 高くありませんでした. Even if we limit our search to Google Books, to weed out other Q&A sites like this one. :)

Likewise, searches for 高くありました and 高くありません find sensible usage examples in texts ostensibly written by native speakers.

Question 2. Furthermore, is it technically possible / grammatical, either currently or historically, to extend this pattern, though perhaps not actually necessary or useful, to say something like 高くある・高くあります instead of 高い・高いです?

Yes, we can. Google Books results for 高くある and 高くあります.

Note the limited hit counts -- this kind of usage is grammatical, but it is also somewhat stilted and only used in certain contexts. The sense of ある・あります has also shifted somewhat over time, and this is no longer just the copular "to be" verb; in modern usage, it often means something more like "there is / [someone] has" rather than just "is".