Saltydog,
be careful about the common names - especially "butterfly pleco" , I have seen gibbiceps(sailfin) sold as such and they can get to 18" or more. Another one I have seen as butterfly is the hillstream loach (stingray pleco) this is not a pleco at all and actually a fish hailing from much cooler waters so it will often do poorly in the home aquarium. The L-052 and L-168 are often sold as butterfly plecos. These will not get too big (5-7") but I find that they are very secrative and like to really hide out. Once you figure out their favorite hideout you can usually find them there 90% of the time. L-200 is nice as is the L-066. I know there are some larger L-200s around but all my L-200s have reached 6" and stopped growing or slowed down dramatically.
Haggisman,
I have an L-191 and I think that the L-190 is very similar to it in that the max size is 10-12" - they are supposed to be the smallest growing Royals.
I have also read that Baryancistrus (L-047 & L-085/177) can get to 12" or more but I have never seen one bigger then 5-6" so I think they grow slowly and in the home tank it would be hard to get them to the size they have the potential to reach in the wild. Still - I have found baryancistrus to be quite territorial, especially the mangos (L-047). They often scratch eachother and tear up eachothers fins and the best way to solve that is to have enough bottom terratory and hiding spots.
Ottos are a good choice and like to stay in schools, they will stay small and IME thrive best with live plants in the tank.
The clowns like the royal are slightly problematich as they process a lot of wood and create massive amounts of waste - this nessecitates large frequent waterchanges and filtercleanings. For low maintenence avoid panaques.
Hypancistrus are a good choice as they stay small and won't harm the plants.
I have found ancistrus to be problematic with plants - they rasp the leaves, especially on large plants. They get to be about 6-8" so not overly large but not small either.
The L-114 is a beauty, mine is 6-7" after 3 years. THough it often is listed as growing to over 12", I have heard that there are supposed to be 2 different varieties. One which gets larger and has smaller spots and a smaller one which has very attractive spotting such as yours.
NICE PLECOS BTW