Any suggestions for really good fragrant roses that grow particularly well in a pot?
In my personal experience, anything but the most modest of roses can be kept for long in an 18" diameter pot. I have Miniatures that are too large for such a pot, if the intent is to house them for years in this manner.
However, here are a few very well-scented small roses I feel will prosper for at least 5 years in a small (18") pot:
'Sweet Chariot' (definitely at the top of my list)
'Basye's Blueberry' (may reach 3 feet)
'Château de Clos Vougeot'
'Gloire de Rosomanes'
'Marie Pavie' (will eventually outgrow a small pot)
'International Herald Tribune' (great for pots, medium strong scent)
'Souvenir de la Malmaison'
I'm sure there are others that qualify, but this is what comes to mind.
I dare say that even 'Fragrant Cloud' could be grown own-root in a pot that size for at least a few years (avoid grafted, because it will grow too large)