we used to have a few colours of hamerite smooth where i used to work when i had to make up garding for the cnc's i used to maintain i would blend the few primery colours (black,white,yellow,red,blue) we had to get a shade that was close to what i wanted. had to make it up in one go mind
handy as hamerite is primer free quick drying and pritty much a one coat job
if you are wanting a simular thing why not find a local paint supplyer that can tint machine enamal to the colour you want or industrial paints are avable in most BS and RAL colours (standardised colours)
go and speak to your local paint supplyer and tell them what you want to do with the paint and how you plan to apply it and thay will be able to help you
i used to sell industrial paints when i was a welding supplys rep and delt with a co. called mannor paints thay did all sorts of paint even paints for hgv fleets
you may have a local supplyer or be able to buy direct look under metal or Commercial transport for types and specs
http://www.shipleypaint.co.uk/index2.php