It's pretty common. I knew a guy who was working in Vegas, LA and Hawaii. He'd do about a week straight, then have 5-7 off then fly to the next one and start again.
The biggest disadvantage of this is that with most groups you will be considered part time (they all have different names for it, we call it part time). Which usually means you can't become a partner, are excluded from the benefits package, are not gaurenteed a minimum amount of hours each month and so on. Some groups even put the part timers on flat hourly while the full timers or partners get the productivity bonuses.
So it's actually pretty easy to do it but there are some pitfalls and disadvantages.