Hi Jon
I must say that I find it quite bizarre that when a specific question regarding the construction of a mail standard is posed that John has answered with a synopsis on the difficulties he had in constructing a mail coif, a different - albeit one of mail - animal altogether.
Just to clarify, the difference between a mail standard (or pissane) and a mail coif is that the former is a neck/shoulder piece usually strapped or tied at the back of the wearer's neck whilst a coif is a hood of mail which covers the entire head - bar the face - and the shoulders. It appears that the mail standard replaced the earlier coif and aventail types (mail hanging directly from the helmet itself) over the course of the fifteenth century.
The constuction of these standards is relatively easy although, as Brendan has mentioned, it may be necessary to use inserts of mail if making a large standard capable of covering the shoulders. Here is a simple standard which I made myself some years ago:

The standard is buckled by four straps at the back and has a liner of calf-leather at the throat to lend comfort and form. Although the basic construction is essentially a simple rectangle of mail, each end is 'graduated' to allow a more comfortable fit. Small triangles of mail decorate the lower edge of the standard as was often depicted on contemporary illustrations including Durer's famous engraving of 1521.


Above is my reconstruction of an early 16thC gallóglach showing the standard being worn with a contemporary uncombed early burgonet and characteristic long coat of maille and below is a reproduction from Gerry Embleton's 'Medieval Military Costume' (The Crowood Press, 2000, ISBN 1 86126 371 6, p. 62) showing the standard's strapping at the back.

My standard just took a few evenings to put together and was well worth the effort. Hope this helps.
Good luck and sl�