Because that's all I need.
just get one of those little Android miniPCs and load some custom firmware. http://www.geekbuying.com/ There's a community online for them (forgot the name).
If it's not ever going to move, there are SMARTBoard systems that pretty much every high school I know of uses nowadays. It's quite impractical and probably way too expensive but maybe it's what you need.
Both the university here and back home have something similar like this, which is basically a giant tablet table:
http://www.medgadget.com/2010/11/sectra_visualization_table_launched.html I could snap a picture if you want! It runs Windows 7.
I have no idea why this doesn't exist. The pointer could be a game controller with Bluetooth for the buttons. So, I guess it's a HATWAC. Boom, Google Play is now a gaming console/entertainment system, a whole new app ecosystem. Give them five years, and they eat XBox's lunch.
Update: Actually, it almost exists, but it doesn't have a pointer, and it's external.
http://www.android.com/tv/ Why doesn't Google just start shipping the whole package? Then you don't need the puck, and the control is better.
24 inch? http://mashable.com/2014/08/19/fuhu-big-tablet/ I would still be tempted to get a massive flatpanel and attached an Android stick of some sort to it, so you always have an upgrade path.