You are posting in the websurfer bulletin for questions on the iopener. You need to go here and click on the "iopener technical" http://www.linux-hacker.net/cgi-bin/UltraBoard/UltraBoard.pl?
Anyhow, all the io versions are modifiable. as well as the websurfers.
It really depends on what you mean by extraneous modifications. Let me just say that those who have done the iopener mods haven't said they regreted it from being too extraneous.
Depending on what mods you want. if you just want to run a harddrive then all it takes is flashing the bios chip, getting a special ide cable for your 2.5 inch laptop drive. Either way, it's been a blast modifying the iopener. Definately the iopener is more of a hobby and not a way to get a cheap computer. If you keep it to a basic windows install then you can keep your hardware costs down to $100 or less, making the totally with a $150 iopener $250. Otherwise chances are that it'll cost you more, so it's probably better off for you to get a regular desktop if what you want is a cheap computer. But as a hobby, it's great.
Try using the search button first for keywords. and try reading the "iopener technical moderated".