I suggest you start by reading these two discussion thread to learn the difference here of XBMC for Xbox and XBMC for Linux/Windows/Mac:
http://forum.xbmc.org/showthread.php?tid=36788
http://forum.xbmc.org/showthread.php?tid=30640
Also make sure that you read:
http://www.gnu.org/philosophy/selling.html
and:
http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
and of course also:
http://xbmc.org/legal/
Knowing that MythTV is GPL just like XBMC also see this list of others who sell hardware bundled with a MythTV pre-install and pre-configured;
http://www.mythtv.org/wiki/index.php/Com...hTV_System
My own personal disclaimer: I am not a lawyer nor will I take any legal responsibility if you go ahead and sell XBMC pre-installed on a hardware platform, but I will tell you about my own interpretation of the GPL (GPL version 2) that XBMC is distributed under;
First of all, the XBMC Media Center software is free and under the GPL (GPL version 2) license, and even though you may not charge for the XBMC Media Center software itself you can charge for the service of redistributing it and the work you done packaging/bundling it with hardware, packaging and handling, pre-sale and post-sale support, etc.
Note that you must somehow clearly inform your customer openly that the software itself if free under the GPL, do not misrepresent that fact or it could count as fraud. I do not know if you know this or not but remember that most set-top-boxes and also network routers that are sold on on the home and small-office market today contain GPL licensed software, either in the form of Linux based operating-system and/or as applications or services running on the operating-system.
Other than that you also have include a copy of the GPL with your product, and best/simplest is also to include a copy of the full source code of the exact version/revision of XBMC that you pre-installed, (either a copy of the source code on a CD/DVD, or a copy on the harddrive of the box, or provided on your website), important is that it is the full source code of the exact same version/revision of XBMC that you pre-installed. What they usually do in include a printed manual with does contain the GPL and either the source code on a CD/DVD or a link to where a copy can be downloaded on their website, (website download is more common among larger companies and CD/DVD more common among smaller companies).
The
XBMC Online Manual and the
XBMC Online FAQ are also open sourced, however they not licensed under the GPL but instead currently licesed under the Creative Commons Attribution-Noncommercial-Share Alike lisence version 3.0, a license which is much more restrictive than the GPL when it come to using the content for commercial purposes, this means that you can not sell the content of it, (we might change the license of the wiki in the future but this it currently the case).
http://creativecommons.org/licenses/by-nc-sa/3.0/
Yes the words "XBMC", "XBMC Media Center" as well as the XBMC logo/logotype are copyrighted so you must abide by that copyright, thus you can not start a company or website called "XBMC Limited", nor advertise that you are official/certified retailer of "XBMC" software, at least not unless we would give you approval to do so, (something that you can not expect us to do as we do not even know you).
So in conclusion, to me you are more than welcomed to make and sell a such XBMC for Linux pre-installed and pre-configured hardware boxes as long as you comply with the GPL and abide by our copyright of the "XBMC" name and logo/logotype. Currently though you may not copy the content of the wiki to use for commercial purposes, (sorry).