Properly executed, the paddle float idea can be very successful. Kudos to those who actually practice in a operational environment before the need arises. As has been pointed out, there are other options as well.
When you have a larger very stable kayak as sunday does, there are lots of options. The boat has the stability to support nooses, ropes, ladders, etc, especially if a partner is available to assist (although they do not all work for all people). Notice here though that there is no need to be able to reach across -- you just need to get enough of your body on board before your legs slide under the boat (keep kicking). Note, let the boat tilt to keep your threshold height low (Oasis shown).
The smaller, narrower boats are not so forgiving. If you don't start out prone and slide across as Leif suggests, there is an excellent chance of capsizing the boat again before you get aboard. A successful sequence might look like this (Revo 11 shown):
1. legs out
2. push the near rail down as you slide up and over, kicking to keep your legs from slipping under the boat
3. wiggle/pull across until stable. Then roll over.
Looks simple but requires practice to find the technique that works for you, your partner (if appropriate) and your boat. You'll find the best forum advice and demonstration videos are not necessarily appropriate for your needs and operating conditions. As inconvenient as it may be, actual experience is so much better than learning in the middle of the ocean or lake with your gear adrift (as I found out the hard way). Do it if you haven't already done so!