Source control is required BECAUSE it's a multi-person project. We can't have two people modifying the graphics functions at the same time, someone's changes will be overwritten. Especially since we're all in geographically different locations that vary time-wise, we need a way to guarantee that only one person modifies a given file at a time, hence source control is required.
When you say "emulators a tiny little things", how do you define little? If you mean they aren't a million lines of code, your probably right in most cases. But something like Frodo consists of many files and many discrete parts that make up the whole. I wouldn't call it tiny by any stretch. It's not the Windows 2000 code base, but it's not Eliza either.
Yes, there are many C64 emulators, but only one that any of us are aware of for PocketPC, which is no longer supported or developed and was left in a half-working state. So, because MANY people want it, we're trying to deliver it, for ourselves and everyone else.
I'm also not sure what you are referring to when you say "...people here are very good at porting existing emulators (and then selling them off as their own work...". I don't think anyoneis saying they wrote the games or systems they write/port emulators for. You seem to have a gripe with some people, I for one (or two I should say, shapeshifter already said it), don't know why.
Hey, do us a favor, if a C64 emulator is not a big deal to you... PORT IT! Please, save us the time and effort! Not a single team member while be in the least bit upset I suspect, we'll thank you very much for it.
I do web programming for a living by the way, but I also make decent money on the side from PocketPC software. I suspect that ultimately I could in fact write my own C64 emulator, I've done plenty of things in the past that I'd put on par with it (my own language with compiler and the guts of my own O/S for instance). But bragging aside

, the point is, why would I do it myself for one, and second and more importantly, I most definitely do not have the time. I have a full-time day job, my side PocketPC development at night, a part-time band and, last but absolutely not least, a family with two kids. If breaking up even a trivial task, as you imply it is, into many parts makes it easier for everyone, so much the better.
...and so I said to Mr. Gates: "$640 billion should be enough for anyone!"