Assuming I'm smart enough to do that (which I question) how much would something like that cost?
It wouldn't cost too much and is not difficult to do. If all you want is 200 lumens output I would say you could put something together for as little as $50 or up to whatever amount you want to spend. If going this route you may consider one of the Moddoolar body systems.
As mentioned before the Surefire L1 is a great light and if you get one that can handle rechargeable batteries, the output can be right in the neighborhood of what you are looking for. I love the L1.
Finally, I almost hate to mention this, but Surefire is supposed to be releasing a new version of the Backup series light. Knowing how Surefire is this could happen next week, next month, next year, or never. The style, size, and output sounds right for you and it is supposed to be offered with a choice of switches, one of which is similar to what you described. Let's all hope for the best and for this to be released soon.
Sent from my iPad using Tapatalk