I've gotta say that this is the first I've ever read of anyone having such an idea. I have not read or heard about anyone doing such a thing.
Honestly though to me, I think it would be a good idea that has merit....but not worth the risk and effort to do.
I used to design and specify industrial chemical feed system equipment, and having a large hatch or bulkhead fitting on tanks for future potential clean out and maintenance was often something that would be considered. The track record though shows that not too many folks need it in the "real world"
__________________
|