Last April there was an hackathon at my university and TinkerKit provided a bunch of kits; they said they could be bought through arduino.cc, so they probably just ditched the TinkerKit website to bring everything together ([The libraries are still on GitHub though](https://github.com/TinkerKit), at least there's that).
I was annoyed with TinkerKit's wire arrangement for their 3-wire connectors. The wire order for most standard hobby servos (e.g. Hitec) are [signal, +v, g], but TinkerKet went with [+v, signal, g]. That means I couldn't easily use most hobby servos with their system. I'm kinda happy TinkerKit's wire arrangement didn't become a more popular standard.