Keep in mind that it's going to be a pain to find a console that's able to have the JTAG modification done on it.. Are you guys sure the OP isn't just grouping all 360 hardware modifications into a single term dubbed "JTAG?" The reason I'm asking this is because I've came across dozens of people who seem to think JTAG is exactly the same as RGH, so they want to keep calling it JTAG because they're too busy herp derping to learn anything.
Also, a Xenon is garbage, it's a lot more useful for target practice with a high powered firearm than anything else, it might also make a neat doorstop. Also, if you're really thinking of RGH instead of JTAG, keep in mind that RGH on Xenons sucks majorly, and they have the longest boot times out of all 360 revisions.
With some of the more recent glitch chips for RGH, you can tinker with stuff to get the boot up time to pretty much be instant. Also, what one of the people who commented on this thread saying that the RGH modification has gotten more difficult to do obviously lacks the proper knowledge of it. Just because RGH2 and RGH3 require using different points to solder your wires to, doesn't mean it's more difficult. Not to mention, once you have your CPU key, you'll always be able to perform the reset glitch hack on your 360, it just may take a bit for devs in the 360 scene to get everything working how they want when a new kernel patch is released.
Heck, I'd say it's gotten a lot easier to RGH a 360, because most chips that are being sold now no longer require the standby clock point, as newer glitch chips can generate the 48MHz needed with an onboard crystal oscillator.
Basically, if you can perform the JTAG hack on a 360 without issue, it won't be a problem to RGH a console, it'll just take a little bit more time. FAST, I'm not trying to insult you in any way, I'm just saying it's not as difficult as you made it out to be.