I used to produce my own vege-diesel and used filters I got from the local Home supply store (HD, Lowes). Now I know you stated WMO, but maybe this will give you some ideas or not.
I included the rig I made for filtering the bio-diesel, but I am thinking that you could just use a simple oil filter with the micron rating that you need instead of the water filters I was using. All you would need is a remote oil filter mounting boss, you can get those at performance shops or online like Summit Racing.
The pumps I used were cheap Harbor Freight 1" water pumps, used in series flowing through one filter then feeding the other. The last filter was an oil/water separator.
Ran this rig for 2 years in my '03 Chevy with a Duramax with no issues.
If you have any questions on the setup, if you think it may work for you, just shoot me a PM.