Jtaggged xbox 360 will do what you want + emulators and just like everything else as long as you have a paid for copy of your game I don't think anyone will come knocking your door because you have actually paid for your game legitimately . Microsoft won't come knocking for modifying the 360 . It's just like using custom firmware on any other device , Only problem is you cannot play on xbox live it will kill the console as soon as it connects ! You can however still play online with other jTag or RGH users
For me , I have a jTagged xbox 360 for offline play and I had one for online play which I upgraded to xbox one as soon as it released ! Best of all worlds eh ? Call me a geek but I had a big collection of games from when I was a kid from different platforms and kept them all ,so I like to use them with emu's But It's hard to find a taggable 360 these days tho or one suitable for reset glitch hack . Anything with dash 7371 or below can jTag , I'm not sure which old dash can be used with RGH but basically the xbox must have never been updated online . JTAGGING or RGH is not illegal , but how you use it may be .
" ie game piracy " IS illegal But custom firmware are not . So if you wanted to use a modified 360 for different region games I couldn't see a problem with it
Also , I think you can change your 360 region settings but you will not be able to change back . It's been a while since I've been on the 360 forums years in fact .