Zindra has parcels already set...

Nobody here is thinking laterally enough. If the demand is for waterfront then fix it in software; allow a parcel border to be attributable as "waterfront" - a flag which causes the renderer not to show any land or objects beyond the parcel, when the border is in-viewer from a location inside the parcel. Hey presto; sunsets and cheesy beach crap for everyone that wants 'em.

Or surround your crap ghetto inland parcel with megaprim screens - with images of water on them.
That would be "better" (??) as
1. Rectangular islands with 90 degree corners would never look nice, particularly if the terrain is sloped
2. The Linden water level could be many meters below ground level, so you'd be on a rumpled flying carpet rather than on an island.
3. A neighbourhood of this sort of parcel build would look wonderfully crap from the outside.

That sort of solution might seem ok to someone who only experience of mainland ownership has been in the interior wastelands.
To someone who actually owns oceanfront land, that sort of solution would be intensely puke-making.
Some of us like to go in and on the water rather than just looking at it. We paid high prices for the benefit.

Yeah! and remember to take home any litter you may have dropped.