Вот насколько Энгл подобную идею сделал шикарно, а у дизеля как то не получилось 
http://cs6054.userapi.com/u2047617/video/l_30ad71de.jpg
PS но мы любим их не за дизайн 
А вот что сам автор пишет:
The amp looks great and we never have seen an Engl Retro.
The holes reminds me maybe on a Splawn. You have to
understand that it´s not necessarry for us to copy.
Further .... for my personal taste this is the best sounding
Diezel amp also for low gain settings.
There are as many opinions as people and there is no reason
for a drama. Peter Stapfer is thinking about a metal grill option
which is boring after 20 years.
Again ... for me the D-Moll is a good looking and good sounding
Diezel product. Not more and not less.
Amen