There are a lot of SL6 oil pans out there but the front sump is a hard one to find.
The rear sump truck pan is more common and I would modify one of those for a fast solution to your problem.
Cut-off the rear sump, flush with the remaining pan floor, trim the sump piece to fit the front of the pan then trace it's position onto the pan floor. Carefully cut the traced front section out, cut outside the lines so the new hole / metal piece that comes out is a little large, then swap the two pieces front to back and weld.
A dry sump system will still need some type of special pan to collect the oil, that system also needs a special "scavenging pump" to pump the oil out of the pan and into a holding tank, then lots of other hoses and brackets to plumb and mount everything.
DD
