Kev...Acually I think the only suitable place for long term liveaboard on st. thomas is on the east/seast coast with redhook and vessup being the areas where everything is centered. It is quite crowded but these are protected areas and not open roadsteads. I believe slip fees are around $10 a foot per month but there are probably electric and liveaboard fees as well. I know that some DO live on their anchors or moorings in these areas. Unfortunately, there is no easy commute to the airport area from here and as I recall, the drive is about 45 minutes.
Linbergh is fine in settled weather but is completely open to the south and swells can be quite large in the right weather. Not a long term anchorage.