I totally agree that both iOS and Android versions should exist. But, one big problem with Android is that there are SO many different permutations of it out there. My wife had an Android-base phone before switching to an iPhone, and some apps work fine on some Android devices and don't work on other Android devices (comparing with friends and co-workers). Android is open-source, allowing the various device manufacturers to tweak and customize it for their individual desires. In fact, there are different "versions" of Android on different devices by the same manufacturer! Unlike iOS, there is no one definitive version of Android and that can make it hard to code a reliable app for it, depending on what the app does and which API's it relies on. However, for this application where a simple menu-selection user-interface, entry fields for body dimensions, simple algebraic math, and display of results, I'd expect variations in Android versions probably wouldn't affect it's performance.
[TnG]R1ckx, I got another idea that probably should be in the app since it's not difficult to do - being able to set input units as inches or millimeters. The default input should be millimeters, and (I haven't poked around in Pepakura enough to know whether you can change the units it uses) output I'm guessing should always be millimeters regardless of input units since that's what Pepakura uses (unless there's a setting where its units can be changed). This would enable U.S. users to measure themselves with standard tape measures in inches and the sizing app returns the scale in Pepakura's millimeters.
