Thanks for the additional information, Mark!
A 2 in 1 computer is a standard laptop, but with ability to disconnect the display from the rest of the computer (keyboard part) and continue to use it as a tablet computer. Because of that, all 2 in 1 come with a touch-screen display. The touch-screen display works in the "laptop" mode as well. While in "tablet" mode, you can continue to run the same programs, only without the physical keyboard, so you need to use the touch-screen. You get a lighter, slimmer and more mobile computer compared to a standard laptop computer.
A "tablet" mode is usually used for presentation purposes or for similar scenarios where you don't need to rely on the keyboard input that much. Another example is doing simple tasks such as listening to music and watching the videos. It becomes very easy since you only need to tap on the screen, similar to when using a phone or tablet. When you need to work in Excel with the physical keyboard, you can reconnect the display in order to switch to the "laptop" mode.
Apart from disconnecting the display, you can also rotate it. 2 in 1 computers usually come with SSD instead of HDD; however, you can also get a HDD-SSD hybrid which is also good. Screen size ranges from 10.1'' to 15.6''.
Since you would like a 15.6'' screen size for 2 in 1 computer, here are the best ones:
1. Dell Inspiron 15 7000 (7568)
Review link: http://www.techarp.com/articles/dell-inspiron-15-7000-7568-2-in-1-laptop/
YouTube link: https://www.youtube.com/watch?v=rmEQgisMAQc
2. Asus Transformer Book Flip TP500LA
Review link: http://www.notebookcheck.net/Asus-Transformer-Book-Flip-TP500LA-Convertible-Review.152263.0.html
YouTube link: https://www.youtube.com/watch?v=8sf5O9M_sKU
3. Lenovo Yoga 500
Review link: http://www.notebookcheck.net/Lenovo-Yoga-500-15IBD-Convertible-Review.150778.0.html
YouTube link: https://www.youtube.com/watch?v=g6Tnge2aCXY
4. HP ENVY x360
Review link: http://www.notebookcheck.net/HP-Envy-15-x360-Convertible-Core-i5-6200U-Review.154485.0.html
YouTube link: https://www.youtube.com/watch?v=E_DGd7QN290
These models all have a powerful processor so you don't need to worry about the computer running slow. As far as the raised keyboard goes, unfortunately, you won't find it with 2 in 1 computers since they need to be as slimmer as possible. I suggest checking the YouTube videos for all of them to see more information on them.
I hope this helps!
Let me know if there is anything else I can help you with.