I'd love to see postings from folks that have purchased the Cen-Tech Digital Battery Analyzer (66892) from Harbor Freight ($70).
Although it was designed for starter battery analysis, it does measure internal battery resistance in miliohms.
The most valuable postings would be those that can measure or map Amp Hour rating of known good deep cycle batteries to internal resistance readings on the Cen-Tech tool.
Another method of mapping would be to figure out what to enter for CCA for a given AH rating.
This would allow valid readings of the bar graph (battery capacity) at the top of the instrument for deep discharge batteries.