[name_m]Bramwell[/name_m], nn [name_m]Bram[/name_m], is great! While nickname options are not a deal-maker or -breaker for me, as much as I love [name_m]Rockwell[/name_m], I’m not wild about [name_m]Rock/name_m as a short form and might consider that.
My favorite is [name_m]Bramwell[/name_m], closely followed by [name_m]Rockwell[/name_m], [name_m]Branwell[/name_m], [name_m]Maxwell[/name_m], and [name_m]Wells[/name_m]. [name_m]Roswell[/name_m] is lovely but… aliens.
[name_m]Bramwell[/name_m] is my favorite of the bunch too. And [name_m]Bram[/name_m] sounds very cozy and strong.
I also know what you mean about [name_m]Rockwell[/name_m]/[name_m]Rocky[/name_m]. I love the [name_m]Norman[/name_m] [name_m]Rockwell[/name_m] and [name_m]Rockwell[/name_m] [name_m]Kent[/name_m] artist associations, plus I also think of Cornish rock walls, which are to me pleasant associations, but the [name_m]Rocky[/name_m] thing is less pleasing.
I have an ancestor who was named [name_m]Chester[/name_m] [name_m]Rockwell[/name_m] [name_u]Perry[/name_u] (which I actually love as a name) so for me [name_m]Rockwell[/name_m] would have been a middle.