I'm not sure it's a better solution for actual (black hat) hackers than paying for a VPS with a prepaid gift card or bitcoin (unless they need the webcam) but there's certainly some spy-movie appeal to it.
Last year I did a talk at BlackHat EU on abusing MiFi hotspots to do this, only using the hotspot to attack the wifi network and tunnelling back over 3G to an out of band C2. I've got a lot further since then and have working PoCs that can do this.
They're ugly, but they work and work well.
I would have certainly liked something less expensive to play with too, but this $160 thing has two USB ports and an eSATA port which will definitely make things somewhat more interesting -- my SheevaPlug has been struggling to keep up with the USB disk access... I also saw that there is Gig ethernet on this "devkit"-yellow-thing. I am almost convinced of getting one, but I will sleep on it just to make sure this is not just an empty geeko-consumerism moment.
Personally, I've set up a cheap router [1] with OpenWrt [2] with similar privoxy functionality, as well as a Wi-Fi hotspot and a webcam + motion(1) [3] for surveillance as an experiment. This might be an alternative if you want a small, low-power combination of hardware and software for privacy- or security-oriented applications right now. The hardware was sadly too slow to handle 2 FPS @ 720P video capture from a Microsoft LifeCam HD 3000 camera but it was usable with a 640x480 no-name cam from eBay.
I'm looking forward to mesh networking on OpenWrt.
[1] A TP-Link TL-MR3020; it's $35 where I'm at. I also had to use a powered USB hub and a USB flash drive for a pivot overlay file system.
[2] OpenWrt is quite possibly the most underrated Linux distribution from an administrative standpoint due to how it manages configuration and packages. See http://wiki.openwrt.org/toh/tp-link/tl-mr3020 for how it handles my particular router model.
[3] http://www.lavrsen.dk/foswiki/bin/view/Motion/WebHome