Yet Voynichologists rarely have much of an interest in novels: and anyway, they don't (as a group) exactly amount to anything that might sensibly be called "influential". So: novels making use of the Voynich Manuscript would have to be aimed at the mainstream, while simultaneously providing a mini-introduction to the (real) VMs to bring readers up to speed. I have to say that this seems a fairly awkward mix, which would only work under certain conditions.
By way of comparison, the joy of "The Rule of Four" to me was that its two authors were trying to bring art history to life - but really, they were non-typical novelists, weaving a very particular kind of novel around the fascinating Hypnerotomachia Poliphili. If their next novel turns out to be based on the Voynich Manuscript, I think they would probably be able to carry it off: but I have to sound the warning that most other novelists would probably fail.
(Another danger is that a tiny piece of evidence emerges about the VMs before your novel finally goes to press [there's usually a horribly long lead time in publishing] which causes one or more of the art historical assumptions you've used throughout the book to collapse abruptly. )
Anyway... "The Voynich Covenant" by "ex-special agent" Richard D. Weber is currently up for grabs for publishers: some foreign language rights have already been sold (good news for Bulgarian Voynich-novel-o-philes). There's more on the author's "dark protocols" website (if you can stand the visual clutter). Going through his book pitch, my heart inevitably sank just a little when an enigmatic stranger called "R. C. Christian" and a Jesuit priest (a hearty staple of Victorian penny dreadfuls: at least Dan Brown had the sense to upset Opus Dei instead) each pop up, but what can you do? To me, part of the thrill of the novel is seeing how its author takes a set of cliches and sets them on fire: but put too many of them in a row (like "beautiful forensic profiler Madison Chase") and will it ever catch ablaze?
What should we call all these novels? 'Voy-niche' publishing? As a publisher myself (albeit on a small scale), I find the whole idea quite awful: the Voynich Manuscript still falls short of being a cliche well-known enough for a novelist to be able to turn on its head with any dramatic effect. It's too marginal: the last big mainstream VMs view (Gordon Rugg's Cardan Grille fakery) punted out there was unhelpful at best, nonsensical at worst, and fell far short of setting the world alight - basically, Rugg's 'no-message message' is not really a great premise for a novel. Wired (bless them and their ex-NASA cotton socks) should do a piece on my book instead: Averlino's story is more amazing than fiction. But that's the beauty of the truth, isn't it? ;-p