When originally I pulled out and inspected the oil sump screen it was clean so I reinstalled it and proceeded to investigate elsewhere with pressure checks, etc. I measured the play on the crankshaft and it was right on and the rotation seemed to be normal. After taking some time to ruminate on the issue and with some good suggestions on the forum I once again went back to investigate the sump even though I thought I eliminated it as an issue it still seemed to be the likely culprit. So I again pulled out the oil sump screen and this time I stuffed my el' cheapo bore scope in to take a look and I was not expecting what I did find. I don't remember stuffing this in any opening but the evidence is glaringly there....this is what I found:
[IMG]

[/IMG]
And the same offensive thing viewed from down the dipstick:
[IMG]

[/IMG]
It turns out that a paper towel got in to the sump. I likely put the paper towel in the prop governor opening overnight to keep critters out and it must have inadvertently been pushed in via the prop governor opening as I was trying to maneuver the prop governor in through all the wires, hoses, etc.
With all the research and tests I've done trying to isolate the issue I learned a lot more about this engine and built a few extra tools in the process. I'm actually thankful for what I've learned through all this. Other than the many weeks of downtime I didn't really spend many dollars to figure it out. I suffered more emotionally than anything else. I actually saved money just in the aviation fuel I didn't burn while I was grounded... I have removed the offending paper towel and will button the aircraft up for another flight tomorrow.
Thanks to the people who jumped in to help. I hope this may help someone else with similar symptoms in the future.