The article talks about the Pivos box already, it's supposed to be (check first!) this one:

http://www.amazon.com/gp/product/B0088IGPM8

Not affiliated, no experience with that thing, but I think that's the only device with hardware decoding support as stated by the article.

Practically any device (eg, $60 Deal Extreme set top boxes) has some hardware decoding these days (H264 decoding at least). Whether it is used by XMBC is another matter.

I think all dual core phones and up support 720p decoding pretty well.