Having just watched Doubleboost's item on the Diesel exhaust filter autopsy, I came to me that one may possibly recover the filter unit instead of having to replace the whole thing.
Just how it would be done I'm not sure, so I throw it out for discussion.
Maybe one could use some kind of solvent to clear out the matrix. Perhaps, if you could remove it without damaging it, you could use an ultrasonic bath to clean it. Sort of 'shake out' the particulates.
Or, perhaps (purely as an experiment,of course) you could simply replace the matrix with glassfibre wool.
If the solvent idea worked than you could arrange the filter housing so that it can be taken apart without having to weld it up. Maybe a couple of flanges and a few bolts.
But even if you have to re-weld it, that isn't such a big deal every seventy thousand miles or so.
Any other ideas ?