Kala make a few spruce top ukuleles (including their travel ukulele). I have their Lacewood soparno (which has a spruce top) and really love it. It's a very well made ukulele and the sound is very immediate and forceful. You can read my full Kala Lacewood review here but in a capsule review: buy it.
Kevin Loh displays incredible chops on a Kala Spruce (with maple back).