I have the same issue here. I have several clients who are technically competent and who would like to have fully super-user access. We like to keep a super user account for ourselves across all of our clients' sites so it would be really useful if a 2nd SU account could be set up for the client too.

Anyone know if it can be done? Is it as simple as changing a user 'type' in the database? If so could someone point me at the right table/field?

Thanks in advance.

"super user" actions are hard coded in. I had to figure out what functions I wanted changed and then update it to not check if it was a "super user" but rather if they were in the admin group or not.