If you want to buy a cheap yet decent amp here in ol' Europe and are not handy with a soldering iron, you're essentially screwed. Even the BTech BT928 requires quite some modding, and even then the concept still is very simple. (Dunno whether I'll try to mod mine any further, the trusty Onkyo receiver's headphone out is pretty good as-is.) The best option would be some relatively simple but decent DIY amp - cmoy, apheared-47 or whatnot.
BTW, I wouldn't use the AV-710 unamped. The alt out does not feature any opamps and the DAC was never intended to drive low-impedance loads. The normal front output which does feature an opamp for headphone driving is little better than onboard sound in quality. I'd rather stick with a Live! 24-Bit then. (BTW, have you already checked whether you could obtain the AV-710 at all? Here in .de you can't.)
IDing a mamaboard should be easy with the likes of Lavalys Everest (the former AIDA32), with a pinch of Wim's BIOS thrown in when needed.