http://makeitfromscratch.blogspot.com/2009/01/homemade-hand-hacky-sacks.html
The Guatemalan wallet is considered the rarest of all Myachis, though there is no definitive proof that this sack still exists. The rarest Myachi that is known to exist is the prototype sack, the "Silver Surfer". Only 3 were made and that was in 1999.
The Punk Pink Leopard has been retired since 2006 so there are no stores or online shops that still carry it. The only place to find it now would be on an auction site or from a collector.
at pancho's shop
There are a number of ways to measure which Myachi would be the "best". For a beginner, the most important thing it how quickly a Myachi breaks in and how easy it is to catch right away. For these players, a corduroy sack such as the Shockwave, the Boss Tweed, the Starting Line or the Braveheart would be the best. For an experienced player, the break in time is not as much of a factor and thus the only real concern is how well the sack jams once it is completely broken in. Again, this is open to opinion, but the three Myachis most often mentioned as the "best" by veteran Myachi players are the Calvin, the Coreyster and the Black Belt.
There are two varieties of waterproof Myachi, though both are rare and have been out of production for some time. The "Neo" is a solid yellow neoprene sack. The "Ron Jon's" is a red sack with a white logo made of the same waterproof material. While both of these sacks are great jammers when soaking wet, they are notoriously difficult to jam with when dry.
While there aren't many Myachi retail locations in Canada at the moment, the Myachi home office does ship internationally. Just call the office at (615) 791-7783. If you are in the Toronto area, you can find Myachi at Tradeopia on Dalhousie St., Joelle's on Brant St. in Burlington or Toy Soup on King Street in St. Jacobs.
Technically, there is no "least rare" Myachi, since all Myachis that are currently available on myachi.com have the same level of commonness, however, the most plentiful Myachi is the Sobe '02, of which 100,000 were made. Since this was last manufactured in 2002 it has since become relatively rare despite this high number. The Black Butter is also often referred to as the "Most Common" Myachi, since it was made in greater numbers than any other series (non-promotional) sack. Again, since it was last released in 2008, it should no longer be considered the "Least Rare" either. The best answer to your question is that any sack offered in the 4.5 series is currently the "Least Rare".
There's no such Myachi as the "Electron M".
Myachi Masters travel all over the country and have been in Utah a few times in the last few years, mostly in and around the Logan area. Incidentally, the worlds best Myachi player is a Utah native, known as Maverick in the world of Myachi.
Old school or rare Myachis are not available in stores or on most websites. Generally speaking, you will only find rares on auction sites such as ebay, though you can often find Myachi enthusiasts willing to sell or trade on the official myachi website or the official myachi forum.
The Snakeskin Tie-Dye was last released in the 0.7 series in 2002. It is considered a very rare Myachi.