Presented in c't 6/2010, 83 there is a cheap (€85 through http://www.gp2x.de/shop/index.php), homebrew-friendly handheld console introduced a year ago that seems to emulate every system (up to PSone level) but the CPC at this time: http://en.wikipedia.org/wiki/Dingoo (following in the footsteps of the GameParks as you may have guessed from the vendor's URL).
It actually comes with a number of Nintendo and Sega emulators pre-installed (other preloads are left out compared to the Chinese version apparently due to licensing issues), and a display on par with the DS according to c't's reviewer, and might be of interest for anyone who sets out to port their emulators (the keyboard would of course have to be virtual, but I'm not sure yet how usable this is without a touch screen on its other home computer emulations - MAME and ScummVM are already there).
couple of extra information:
* Dingux is better than native Dingoo software(including Amstrad CPC 6128 Pituka & Amstrad CPC Caprice): http://dingux.toddler2x.info
* Cheap & secure shopping: http://www.dealextreme.com/details.dx/sku.20217
* Latest news from Dingoo world: http://dingoo-a320.dcemu.co.uk
* Youtube videos (http://www.youtube.com/results?search_query=dingux+emulators&suggested_categories=20%2C28&page=1)
I have one. Excellent little machine, and I like the design, too. It's a shame I don't have the time to play, but it accepts mostly anything!
I can second that. Very cheap yet decent portable emulator platform with nice media player as added bonus.