Well, to continue the discussion, freely acknowledging that you and others may be skeptical about much of the following:
1. I disagree with Taylor's conclusion that "the case boils down to the fact that the author found no other Even Ragland in the course of his search." I think that there is other relevant evidence here, but it seems that the weight I place on certain snippets is different from your assessment.
2. I am inclined to challenge the choice of words you used to summarize Point 2 in my previous comment. You used the phrase "he was possibly middle class," where I would use the phrase "he was evidently middle class." At the time and place, literacy and numeracy (the prerequisites for being a secretary) presumed middle-class background at least.
3. I am inclined to challenge your summary dismissal of my discussion of the similarity of given names. At the time, it was the norm to give children names from the immediate families of the parents, and the fact that Evan used the names Thomas and John for sons makes it logical to look for Ragland families where these names also appear. And lo and behold -- the only known family with both Thomas and John also has Evan. If you can find another Ragland family of the same general time period that uses the names Thomas and John, that will weaken my argument.
4. Perhaps in my earlier post, I didn't place enough emphasis on the exceeding rarity of this surname. A search of the IGI for Ragland baptisms in the 17th century comes up with only 30 records, which are easily broken down into family groups. Even though there were certainly other Raglands in parishes not covered by the IGI, this family is SUPER small.
5. My earlier point about Evan's MATERNAL grandfather shows where the name Evan entered the Ragland family. Evan simply wasn't a Ragland family name until Thomas Ragland's marriage to the daughter of Evan Morgan. Once again, I seem to place greater weight on the names of the children than you do.
I'd like to add one further point: In the general time period of Evan's migration to Virginia, there were three principal points that shipped out indentured servants: London, Bristol, and Liverpool. See http://www.pricegen.com/origins-of-colonial-chesapeake/ For the common practice of kidnapping English children to sell in Virginia, see http://www.genealogy.com/forum/surnames/topics/prescott/636/ St. Decuman is on the coast in the general vicinity of Bristol, which is the type of origin we would expect to find if the two Evans are indeed one and the same.
I carefully examined Charles Ragland's books (a couple years ago, while investigating the false allegation that my ancestor William Davis descended from the Raglands), and his detailed description of a late medieval manor house is useful background reading for anyone who researches the landed gentry of this period. With that said, he clearly relied on secondary sources for the ancestry of Evan Ragland of St. Decuman, which of course isn't up to Douglas Richardson's standards. (And his omission of documentation in his second volume on the descendants of Evan Ragland tends to raise eyebrows, although he did deposit his notes at a repository in North Carolina, and his conclusions for the family in America seem to have held up well for the most part.)
Finally, I think there is a clear course for further research: collect existing documentation for all Raglands in the 17th century (starting with vital records, wills, and Raglands listed in the 1641 subscription to Parliament's remonstrance; and extending to less accessible land records and vestry records), and see if they can all be arranged in connected family groups. Much of this research has already been done, if it is still accessible. The argument AGAINST the two Evans being one and the same is based on the supposition that there was an unknown Evan born in the 1650s to a different Ragland family. I suspect that the total number of Ragland families is so small (as well as being wealthy enough to appear in at least SOME records) that a thorough list of possible fathers could be identified, with each and every potential father compared to the likelihood that Thomas Ragland of St. Decuman's was the father of Evan Ragland, immigrant to Virginia. Perhaps we can turn such a task over to descendants of Evan Ragland, of which there are already a handful here at WikiTree. It would be a fascinating study...