Capensis do grow relatively quickly; my vote goes to drosera burmannii, or any "annual" sundew. Burmannii stay relatively small, a couple cm in diameter, but if you want a bigger plant, drosera indica are annual and get around 24 inches tall I believe.
Regarding all flytraps, sarracenia, nepenthes, they all take some time to grow from seed to mature plants (years), but annual drosera like burmannii and indica will be full-grown in under a year.
Like most sundew, with bi-weekly feeding burmanniis and indica will explode with growth and get bigger much faster. Use freeze-dried bloodworms - crush into dust and sprinkle over the seedlings. When they get bigger, I feed them betta fish pellets instead of insects. It works very very well and my sundews flower like crazy. Both of these items are available at any major pet store in the fish aisles, and they're both really inexpensive (couple bucks).
See my reply to another user here for more information if you're interested in growing these from seed: http://www.flytrapcare.com/phpBB3/post72922.html#p72922