I miss bags the most when I switched to the Pin, but never found any that looked right, and flowed with the fender line. Ended up going with a couple of tool bags, which gives me a place for some small basic stuff.
I've seen a couple of hard plastic and fiberglass trunks, that could be bolted to the solo rack for quick storage, but haven't picked one up yet.
'09 Kingpin 8Ball
'06 HD Road King
'06 Vulcan 900 Classic