A tool like that isn't technically possible AFAIK - the gap between native and managed code is really too great for any automated system to do much with. And even then there'd still be the need to maintain two code bases. WM emulation for Android is very unlikely, but you might see Palm OS emulation via StyleTap - if other platforms are any guide that would only be useful with PlecoDict 1.0, though, and you'd likely encounter the same issues selecting text and handwriting characters in a resistive-screen OS on a capacitive screen that people have had using Pleco in emulation on webOS. And dual-booting is certainly a possibility as you say.
Any poll that isn't explicitly restricted to existing Pleco customers runs the risk of getting spammed by Android boosters (a significant number of whom seem to approach the mobile OS wars with a sort of religious fervor) - only takes one person who really really wants Pleco on Android to post about it in a dozen Android forums and generate thousands of pro-Android clicks. (not really any parallel for that on the desktop side of things, nobody's going to go into a big Windows 7 forum and get everyone to vote for putting such-and-such cool app on Windows 7 out of an abiding love for Windows 7)
I myself am a proud Apple-liking nerd, it's more that the people who feel strongly enough about Android versus iPhone that they refuse to buy the latter under any circumstances tend to be considerably more computer-savvy than the average Pleco user. (at least that's my sense of it) I don't see Android versus iPhone becoming anything other than a matter of personal preference anytime soon - this won't be a night-and-day comparison like WM versus iPhone (or WM versus Android), neither company is going to let things slip that far - and judging by the iPhone 4G leaks, it seems like aside from the lack of a keyboard (not actually that oft-cited an issue) neither platform is likely to achieve clear hardware superiority anytime soon either.
So the size and steadfastness of that Android-only group are a critical question here; they have to demonstrate they're large enough to buy tens of thousands of copies of our software that we wouldn't sell otherwise. And the importance of that is why I'm worried about getting accurate results. Steadfastness is definitely key, since if someone merely prefers Android but would buy an iPhone / iPod if that's the only way to run Pleco, there's probably some combination of other things we can do for them (via lower prices, new licenses, new features, etc) that'll make them equally happy but at a lower cost to us than an Android port. (another problem with the poll, and why there'd need to be a "don't support any new platforms but add such-and-such long list of new features to your iPhone software instead" option)