The Mandler 50mm f/1.4 E46 Pre-A lens can be pre-ordered again.
Here is an excerpt from their hompage:
It is a lens with a dual life. One facet carries forward the classic de-focus rendering and distinctive pictorial charm born in 1961; the other embraces contemporary optical design to achieve a closer focusing distance and higher resolving performance across the entire working range.
Further informations can be read in these previous post.
The lens was sold out just recently; demand seems to be very high right now. Of course, the relatively low price—especially for an M-mount lens—makes this lens appealing to many people.