I'm sure I recall seeing these on sale somewhere as a generic item, but I'm stuffed if I can find them now!

What I'm after is just the strainer that goes on the end of an oil pickup pipe, so that I can make my own.

Have a look on eBay loads on there choose a car that fits the bill, alternatively local breakers.
link

I really need new, and in regular supply.

Put 'Stainless Mesh' into ebay, then pick the gauze size/mesh size you want, then attach to your present pickup.

Cheers,
Nev.

http://m.summitracing.com/search/product-line/melling-oil-pump-screen-assemblies

In the US so may be worth making a big order to cut down on shipping costs?