I wasn't aware that Jesse L Martin, one of the best singing actors, was hoping to finance a musical short for himself but he is. The world collectively fell for his voice on the Original Cast Recording of "Rent." David E Kelley let him sing fairly regularly on "Ally McBeal" (those bar scenes made full use of the many musical alums in Ally McBeal's cast) and then he reprised his star-making role for the ill-conceived Rent movie. Since then he tends to be cast in non-singing roles -- even in musical shows like "Smash"! He's currently the adoptive father / police detective hero on CW's hit "The Flash" and he doesn't get to sing on that show either.
But listen to this -- here he is with two of his current co-stars on "The Flash" (Carlos Valdes and Rick Cosnett) to sing the theme song for Joss Whedon's "Firefly" It's a thank you to Joss who donated to their collective kickstarter project. A fourth co-star is also involved in this would be short (Patrick Sabongui who plays the incidentally gay police captain boss on the series) but he's not in this thank you video. Maybe he sings, too?
Let this double as a cry for action aimed at the CW writers room: The Flash obviously and desperately needs a musical episode. Make it happen in Season 2. To its very entertaining credit your show already embraces "anything can happen" insanity (Gorilla Grodd, hi!) so if Grant Gustin can't sing, just give the other guys all the songs. Make it work.
UPDATE: Grant Gustin can very much sing. (Sorry, I stopped watching "Glee" before he arrived and have never regretted the decision). A musical episode must happen.
Why are actors always so multi-talented? It's unfair. And wonderful.