Here's your 7" touch screen, right here

Archive
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7" touch screen (resistive), ~$70: A13-LCD7-TS - Open Source Hardware Board

Get the 1 GHz, 512MB PC to go with it, ~$70 with WiFi or $57 without WiFi: A13-OLinuXino - Open Source Hardware Board

Impressive. Olimex are also selling the A13 CPU, which are as low as $7 or so in sufficient quantities.

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Please let us know how this well these work for you.

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Someone with a TFT-capable board ought to try one out. I don’t have one.