Is it possible to tune a baritone uke as a soprano?

If I got a baritone would it be possible for me to tune it with the same tuning as a soprano in a lower key? I would think so but I just wouldn't want the strings to break

If you change strings, you can pretty much tune it however you like. I'd try using a standard Tenor set and see what happens. The tension on Tenor strings will be naturally higher if you want to tune to GCEA, so be careful. There are many threads here about string changing, some even have links to tension calculators. I'd find the tension of your existing DGBE strings, and find a string gauge that will give you a similar tension at the higher tuning.

Most (and by most, I mean ALL) baritone ukulele come strung with a low top string. So its really not wise to try to tune that like a soprano, but if you want to try it, make sure to point your bari away from your eyes.

However, our favorite MusicGuy has sets of baritone strings specifically designed and engineered for such a purpose: http://cgi.ebay.com/AQUILA-BARITONE...emQQptZLH_DefaultDomain_0?hash=item5636651693

edit:
Are you wanting to use a Dgbe tuning (with a high D)? A few people have asked this and its possible to do it safely. I'd use the same string on the top string and the bottom string, just tune the top string down to D http://cgi.ebay.com/AQUILA-BARITONE...emQQptZLH_DefaultDomain_0?hash=item3a5407fee4