Keeping a mutable reference to a struct with immutable members

[pineapple via Digitalmars-d-learn]

I found another post on this subject and the advice there was 
"don't put const members in your structs" - 
http://forum.dlang.org/thread/m87ln2$idv$1@digitalmars.com

This doesn't work out so well when the templated struct is 
referring to what happens to be a const array.

I thought I could get it done with pointers, but then I realized 
my data was going out-of-scope. I tried using `Unqual!T 
thing_i_need_to_reassign_sometimes` where T was immutable but 
that didn't solve anything, either.

What's the best way to handle something like this?