I've used "please me no end" as a phrase since childhood. And it's certainly not a new usage, as I clearly remember both my Father and Grandmother using it as a part of every day speech.

Like ysth, I never heard the "please me to no end" variation.

I guess that's the thing about natural languages. They evolved, and continue to evolve, on the basis of common usage. The codification of the "rules of grammar", came after the fact. Hence the irregularities that burst the bubble of rule-bound.

I clearly remember an english lesson in which I was taught that you "take things there; and bring them back", but again just this evening in a US movie I heard an apparently well educated character say: "Will you bring him with us"?

This sounds entirely wrong to my ears, but it, and many other "grammar errors", crop up in US movies and books often enough that I can only assume that they are fairly normal speech patterns in the US. Whether they would be acceptable (to whom?), in written english is another matter entirely.

It is actually a mispeling of "'it wood pleas Smee too know 'enned", from the pirate legend, of course. My research did turn up some cases of the "too" being dropped but I think we can all agree that such a phrase doesn't really make any sense in the context of the legend.

I think I'll switch to "it would please me long time" to avoid confusion / controversy.

Before doing the research that turned up the pirate legend origin, I too thought "I've never heard 'it would please me no end'" but thinking on it more I realized that I had heard that version just not much recently.

And I really think the reason for the shift is a combination of "it would please me no end" having an awkward feel when you try to parse it grammatically (as you noted) and people finding "to no end" familiar (even though with a different meaning, especially since that other meaning is rather idiomatic anyway). So it can be more comfortable to say "it would please me to no end" when you aren't thinking about it, which is usually the case when someone utters a pat phrase. Just like it is easier to say "I could care less", avoiding that awkward "nt" sound that interrupts the flow of the phrase.