I have seen a 8" gold nugget i suggest the clown pleco they stay small 2-3".
If you want an algae cleaner, go with a BN pleco. There are more/different species of Ancistrus than the common brown or albinos that flood the market, some only grow to 3". Clowns are actually peckoltias, they're in a different family, and require driftwood in their diet.
If you can find them, gold spot dwarf plecos look a bit like much smaller gold spots. Here's a link: http://www.planetcatfish.com/catelog/species.php?species_id=157
The only loricariid which was once considered as the true pleco is the Hypostomus plecostomus. The rest are loricariids. Otos are loricariids, not plecos.well i considered all loricarids as plecs