I've always been adept at switching from one thing to another. A different platform, language, framework, technology, project type, whatever was needed. Often I have worked on different unrelated things at the same time. I've even fulfilled multple roles such as developer, architect, project manager and analyst in various combinations.
Employers and customers seem to find this a good thing once you are there, but it's poison when it comes to filling out a resume. It's a weird skill to have, rarely have I ever done the same thing twice, and establishing a track record for some common skill set is virtually impossible.
I have for the most part been able to excel at whatever I wind up doing, in wildly different environments and on radically unrelated technologies. The next day though I have forgotten much of it.
At my current position (contract) at a game company I maintain the OSX version of our MMO game client (Cocoa front end and common C++ game code), wrote the crash handling and reporting system for the Windows client along with the web reporting tool in PHP. I routinely work in C++ on both platforms. I use the OSX version for profiling (until recently we used the Intel compiler on Windows which isn't well supported for many profiling tools) and then either fixed issues or documented them for the other 2 client coders who only work in Windows. Just today we finally started using Visual C++ 2010 as the compiler so I will be working with a Windows based profiler from now on. Plus I am working with Unity Pro to evaluate it's potential use for future products.
All this and I work with PHP at home, I'm working on two OSX apps (a GLSL shader tool and a game) in Objective-C on 10.6 and a music application on iOS for the iPad.
Prior to all this I was a Java architect for nearly 9 years but also spent a couple of them as well as a Documentum architect because no one else wanted to do it.
Go back far enough and I can't even remember all the things I've work with. Early in my career I even did a Mac start up and the founded and ran a Mac consulting firm.
How does this work on a resume? Well it doesn't. How well does this work in an interview? Not there either.
One brain can only manage to know a few things at the same time and everything else will get squeezed out. For whatever reason I pick up things quickly and apply experience to know what's important, what I can depend on, and have confidence I can do a good job at it. Then when I don't need it anymore it falls out the back of my head.
Prove it? Good luck with that. There are likely tons of people who try to fake their way into a job and don't actually know anything. Most companies seeking employees prefer finding people with narrow experiences matching their immediate needs so that testing them is easy. Spend 8 years write J2E(E) apps and the interview is pretty simple. Trying to hire a jack of all trades is not since judging multiple and possibly future talents is really hard if not impossible.
The funny thing is despite my nearly 30 year career I still love constant switching to new things and multitasking. This industry changes every day so there is always something new to work with. There are so many different aspects to programming and industries to work in (though I do love the game universe) that there are still areas to explore.
I may have to explore combining an overview resume with an online in depth version somehow. Having this blog is of course a useful thing since I've covered so many things. I like seeing blogs from interviewees but I bet few people ever read beyond the last job on a paper resume so it's not that useful..
Perhaps a variation on a Vulcan Mind Meld might do the trick!