The 3x4x5 has been mass produced! Get one for just $32 (free shipping!) from Mefferts.com
Finally! A fully functional 3x4x5 puzzle is now available to everybody. After three design iterations, I finally have an affordable, stable, smooth-turning and solid design. This puzzle is very difficult to solve due to the constraints imposed and is a challenge for any puzzle solver.
The video shows 3x4x5 V3, for sale is V4, which is only very slightly different and works even better than V3. This puzzle (V4) has been prototyped.
This puzzle comes as a DIY kit. You will only get the 3D printed parts. You will need to supply your own M3 washers, springs and screws (x6). You will also need one Cubesmith 4x4x4 tile set and two extra singles for the 3x5 sides. Please note that using regular stickers with this puzzle is not recommended, only tiles are suitable.