I INSTALLED ONE OF THESE:

http://www.fishman.com/products/view/classic-series-active-resophonic-pickup

(they also make a passive version of the same thing, but it requires a preamp)

I'm pretty happy with it. It retains the dobro sound, and makes the instrument much easier to record.

You WILL have to drill a hole in the instrument in order to install it. (Maybe two, depending on where you place the battery.)

If you get one, when you unpack all the parts there will be a little clear plastic washer that is easy to miss. Make sure you have it... without it the pickup will short and then it doesn't work.

(Don't ask how I know this.)