They advertise it as an internal mic for their Rover mini travel guitar, but their website also says that it can be used for any guitar! I contacted Washburn and they confirmed it.
Yes, it requires you to drill 1 hole - the mic IS the end-pin and strap peg and the cable plug. But it's just about $30 (was I not supposed to say it?) and it's a condenser mic. And it seems like a much easier installation than some other internals (especially thinking about battery replacements down the road).
I used to have a "mic-in-tuner" by Wittman, which was a really neat little gadget that clipped to a brace inside the guitar. I liked it, but I had to pay a tech to install it and changing batteries was a pain, especially if you have big hands. Drilling an end-pin hole is easier.
I'll ordered this mic anyway (how bad can it be, I'm not recording), but I was wondering if anyone else's tried it.
I'll be sure to report on my opinion after I try it.