Here's the latest design of a table from Julien Vidame and it uses a series of rolling boards that lay flat or stand up to change its length. There are no additional parts that need to be swapped either.

The table can grow from 31 inches to 62 inches in length. At current there's no pricing or availability yet but a working prototype apparently exist and is ready to go into production soon. Check out another shot of it below:



[Vidam Creation via Notcot]