Aw, but I like messing around on a component level!
But seriously, there is only so much that you can do.
Put in some of the unpopulated connectors, add serial interfaces, extend the button connections, add JTAG.
Reworking the memory chips (unless you do that for a living) is going to be difficult.
If you look at things like the Raspberry Pi 2, the RAM is
Package on Package.
There is no way anybody could be updating things like that.
I really would like if B&N released a Super Nook, but I'm not holding my breath.
You have to realize that the Nook basic design is out of 2010.