Okay, here it is.
Go to http://www.ritzelrechner.de/ and have fun.
I have been collecting data and putting them onto an excel spreadsheet and hoping that one fine day I could publish it here for your convenience. It shall be a comprehensive tool in aiding us finding the best possible drivetrain by way of comparing the gear ratio spread which would suit our riding style.
While reading this post over at Bike Rumor, I found the link above posted by bikeshop.nl in their simple comment.
*it goes without saying that it pays to read everything and explore the links to get useful information.
That 2014 post by Tyler Benedict in Bike Rumor actually came from a forum discussion at MTBR, which originally posted by Daryl Smith; a gearing table for selecting chainring for XX1 drivetrain way back in 2013.
The handy Gear Calculator is copyrighted by Dirk Feeken.
What I like most about it is the Compare two Setups bit. In the image above, I compared my current 3x9 versus 1x10 with OneUp (40T). Click here to play around with the setup.
3x9: 22/32/44T with 11-13-15-17-20-23-26-30-34T
1x10: 34T with 11-13-16-19-21-24-28-32-36-40T
You can visually assess the gear steps and also other parameters such as the speed at a given gear ratio and cadence (90 in the above example), tire development for a single crank turn for the gear ratio and wheel/tire size, and many more display options.
What blew me away is how updated the calculator is. In its Sprockets drop down list, SRAM's new 12 speed Eagle is there as well. Listed cassettes are from 9 speed up to 12 speed. If you wanted to see how a custom sprocket setup would fare, no sweat; just drag away the unwanted cassette sprockets from the graphical display and move it out of the line-up. Pretty versatile.
Internal gears are also listed. Have a look at the 'Gearing' list. Rohloff, Pinion, Shimano Alfine, Sturmey Archer and Brompton are a few among them. There's also Singlespeed as well.
For me, this convenience is blessedly an answered prayer.
Thank you Dirk.