Fullsize inline 6s get quite long with a clutch housing to mount in an engine stand from the rear face.
I've thought I might someday try to work out a mount for the stand that would let me mount the inline from the side instead of the end.This would give better access to both ends of the assembly and the load would be moved in nearer the "backbone" of the stand.Probably the stand should be a 4 wheeled instead of tricycle for increased stability.
My thoughts for this was sparked by a picture of a HEAVY duty engine stand made by,I believe OTC for diesels like the N series Cummins and Cat 3300 type,over 2500 lbs.It even had a geared rotator for ease of positioning.
It seems this mounting concept could be scaled down for our inlines.