I recently stumbled across playing the soprano ukulele in 5ths tuning- which is GDAE. Non re entrant tuning,and for this you will need a set of strings made specifically for this tuning.  I purchased a set of Aquila 30U strings ,and restrung a soprano uke I hadn't played in awhile as I wasn't impressed with the sound of it with GCEA tuning. The new strings in the new tuning made it come to life! 
          A friendly bit of advice on these strings- restring a ukulele that requires you to wrap/tie the end of the string at the bridge. The reason I suggest this is the 1st string is thin and it was a bit of a hassle getting it to stay on my slotted bridge-until I came up with a unique way of getting the string to stay in place. 
           If you play fiddle or mandolin,you're in for a treat because you'll already know how to play ukulele in this tuning! Other advantages are you can play bluegrass,Old Time Tunes as well as other genres not usually associated with uke.  There is a book you can get teaching you to play in 5ths and you can buy a copy here

            
          You can order a set of these strings by clicking on the 1st Amazon link to your right at the top of the page. If you have a soprano,make sure it's the 30U set!