I wonder if [EAGLE Freeware] is featured enough to design single board projects with the complexity of the stuff that you are currently selling? Certainly the board SIZE is compatible, but is there a limit on net size, parts list size, etc?
The limit is on board size, number of layers, and paging in the schematics. CadSoft does a pretty good job of making this clear on their web page. The "number of layers" is starting to be a limiting factor as 4-layer boards become more affordable, and chips get more leads. Putting a couple of 64pin LQFPs on an Arduino-sized 2-layer board gets challenging; chip designers are starting to assume that their chips will go on 4-layer boards (placement and requirements for power pin connections.)
Also the schematic must fit on one page that itself is limited in size.
I believe the "one page" can actually be of rather unlimited size, though I'm not sure how that works out for printing, and it certainly gets "inconvenient" on large schematics. It's "interesting" to look at the way that professional schematics (say, the Digilent Inc "ChipKit" board, or the TI LaunchPad") are drawn compared to those drawn with the freeware.
I know that if I use Eagle and design something I want to sell I'll have to pony up for a commerical license, but I wonder what is the lowest cost package I could get away with.
The $49 "Lite" version has the same limitations as the freeware, but permits commercial use. IMO, It's a Very Good Deal. Even the full professional version of EAGLE is a "good value"; not as powerful as some of the truly professional packages, but also much lower priced.