Converting tablet to a touchscreen monitor?

[octoberqueen]

Is it possible to convert a tablet(any manufacturer, any OS) to LCD Touchscreen Display Device? I have one old computer system and I am in need of cheap replacement to my old monitor. Just then I thought of a Touchscreen Tablet, if possible, will serve my dual purpose- as mobile device while traveling and also as a monitor while at home.

My system has a VGA output. So the tablet needs to have a VGA Input, right? Or a DVI, HDMI input port, if I am using some kind of VGA convertor. Is there any tablet in the market with this spec? I have seen tablets with HDMI output but never saw anything with any display inputs?

So, I need your advice, friends.

[nickgr5]

I don't think this should be possible; at least it might be, but it will be time-consuming, it might cost some money and it won't be recommended to someone who's not technically experienced. That's what I think of, though.