Attorney@work had a recent article discussing the important of being a niche attorney – or, as they say it, not being a jack-of-all-trades.
It’s a well-thought out place and the idea, although hardly revolutionary, has merit.
That said, the value of having a niche practice is often dependent on your individual circumstances. In a metropolitan area, creating a niche for oneself is almost mandatory if you have any hope of standing out amongst the thousands of other attorneys; but in a more rural setting, the old-fashioned general practitioner is still alive and well (generally out of necessity, given smaller numbers of cases in any one area.)
The danger though, is for new solos (be they fresh out of law school or old hands on a new path) is to become a generalist not because it makes logical sense (as it usually does for a more rural attorney), but in chasing that pay-day. While a new type of case might be a good opportunity to learn a new practice area, it might also be a good opportunity to make terrible mistakes and do yourself and your client harm. Tread carefully and be sure to ask for help when and if you need it.