Gibson is selling self tuning guitars. The Powertune system was developed by German engineer Chris Adams, and is being distributed by Gibson as an option on their guitars, with a price tag of $899.

This project describes how to make a strobe tuner "The Tune Trainer". It is quite tricky as it involves an Arduino microprocessor and prototyping board, which can be programmed via your computer. The link below lists the other electronic bits and pieces needed and gives detailed instructions.

The tuner has two tuning modes

Strobe mode

Gary Shutt shows how to get the low 7 string sound on a normal 6 string. What you need to do is get yourself some really thick and heavy gage string like 13 through 56 or a 7 string set and just not use the 9. Once you have your strings on, you tune everything down to perfect fourths. Going from the lowest (bass) to highest strings you will have: B-E-A-D-G-B.