There was a lengthy and quite interesting debate regarding the question of balanced vs unbalanced connections starting around here and continued in this thread . Bottom line: there's no clear concensus for short distances, although for long runs it's commonly considered reasonable to lean toward balanced.

There are XLR splitters. About half way down this page you'll see this . Other examples are here and here . The Cobant Y Splitter can be had with one female XLR and two male XLR's for $27.50.