This is Vocaloid 4 in a nutshell: you type in lyrics, input a melody and Vocaloid transforms that into a realistic human singing voice. The Cyber Songman library gives you a US male virtual singer.
Jussi from the clever folks at Klevgränd is a unique, if not eerie, new synthesizer. It emulates a man singing. Yes, you can expect to make some rather lovely sounding male vocal emulations using it.
This rather humorous mashup video from Cutting Room called Whoa-oo-ah Supercut really brings home how the art of lyric writing in Pop might be at an all-time low.