Wow, that's some impressive out-of-the-box thinking!
The OP's situation is something I worry about, as I'm worried my neuropathy will reach a point where I can't use my arms to type/mouse all day. I spent some time researching speech input for coding a year ago, and found a few fledgling solutions, but I'd need to expend a lot of time to get something remotely workable.
Your idea is, if I may say so, genius, and having that as a backup sets my mind greatly at ease, so thanks.
On pairing in general: For a long period of time when I worked at bigger companies (before co-founding my current venture) I pair programmed 90% about of the time.
For the most part I really enjoyed it, we alternated pairs quite frequently and I worked with people at a range of seniorities. I really enjoyed alternating between playing the role of teacher vs learning from someone much better at the (insert programming language, database, business domain).
I think during that time I also had some of the most stimulating and deep conversations about software development. When pairing, pairs have a deep shared context that's hard to replicate in other scenarios.
There are some drawbacks though, the main one being it's extremely full on and emotionally tiring. I'd class myself as a high functioning introvert and after a day of pairing I needed some serious regenerative quiet time!
My advice to someone considering this suggestion would be to try some pairing now with friends or colleagues and get a feel for it and see if it works for your personality and working style.
Hah, I'm stealing that phrase to describe myself too!
I've never "formally" done pair programming, but have sat and coded/reviewed with colleagues for short stints, and generally found it OK.
From time to time I have to do full days (or several days) of workshops, and find those really tiring and emotionally draining. I always think I fare better 1-1 with people though, so if pairing was a necessity, I'm sure I could adapt.
The solution I always imagine is paying someone or having my employer pay someone to strong style pair program with me. Perhaps a student, junior developer or even someone unfamiliar with software development entirely.
For those unfamiliar with strong style, this rule sums it up: "For an idea to go from your head into the computer it MUST go through someone else's hands". Like the standard driver / navigator pair programming technique but with the navigator never touching the keyboard.
In the case of someone completely unfamiliar with software development I imagine that there would initially be a dramatic high / low skill gradient between us, with the person essentially transcribing. However given the intensity of the practise I think this gradient would level out quite quickly.