Extremes of the xbox, much less vaguely practical ones (seen the price of large IDE drives these days?) without going into fun like the XBOX Xtender (multiple drives in a system, not really all at onc is not my forte.
https://www.xbmc4xbox.org.uk/forum/viewtopic.php?f=14&t=649 seems to be the topic of choice to cover SATA TO IDE/PATA conversion tools.
It seems like a system limit as well. No distinction between xbox games and homebrew for this one.
With that said are you likely to need the space? Every non arcade, non optical console clocks some 22 gigs (
https://gbatemp.net/threads/complet...r-collecting-and-history.507129/#post-8043597 ). Even with ROM hacks that is not likely to rise too much.
The PS1 emulator is kind of workable and that might get things a bit higher, also if you wanted to drop the N64 games from the list above (mad respect for the n64 emu authors working on the original xbox but in practical terms today it is not something I would suggest) that is going to be some 4 gigs if memory serves. Not sure what the MAME set likely to do well for the xbox (final burn alpha) clocks but I don't imagine it is too far off the console collection mentioned above -- you are not going to be doing all the greatest current arcade boards on it. Found a 2017 vintage discussion of Final Burn Alpha and its complete ROM set apparently clocks 9.33 GB compressed. Updates were still happening as recently as May of this year though.
Having a poke around
http://www.abgx.net/filename/ then we could start to put numbers together for a complete collection of commercial xbox games. Sadly it does not have a size listing in that text file and sizes were quite variable (most games in Scene releases were between 1 and 3 gigs in my experience, though plenty went higher), to say nothing of the ability to trim things.Also if you wanted then DVDs are an option in this.
Knock out the Japanese dupes and either NA or PAL region dupes and that number will drop considerably (PAL releases were also often split by country). Go further and weed out things you would rather have on PC (any PC still vaguely workable for day to day stuff will be able to play every xbox era game happily). Further still and trim the fat (do you really care for Antz Extreme Racing?) and things get better. Nothing stopping you from holding some of these... less likely to be played titles in reserve on your PC somewhere as well and maybe even create scripts to copy it down from a network share somewhere.
While you could still use it as a media player too that can be done over network which you could build a NAS for if you wanted, and I would say get a raspberry pi or anything that supports a proper version of kodi instead as it is far more modern and handles things far better.
Commercial games being straight network loaded is not going to happen outside of SAN scenarios (don't), some homebrew stuff could be done but with the stuff covered above it hardly seems worth it.
