Open-sourcing it would definilty make things much easier for everyone involved, and probably also bring in more outside contributors (which would speed up the process of making it completly stand-alone).
It would also offer a nice chance for a promotion drive to attact more players, and the Linux crowd certainly loves open-source games.
A Kickstarter (or better Indigogo, because Kickstarter is difficult to set up if you are not in the US/UK AFAIK), might be a nice incentive for you to finally let go of the (very unrealistic I might add) commercial aspirations you seem to have. But please don't make the initial open-sourceing barrier too high (maybe 500, max 1000$?), most of the money from these funding drives does not come from real funders, but rather people looking for cheap preorders, thus a open-sourcing drive attracts far less "funders".
You can always add additional goals if people are really exited about it and pledge by the masses.
But really... I think it's the only chance CQB will have to come out of the total obscuity it is in right now.
If you look at the download to install, and install to actually start and test (and then the actual player retention) ratios of "free" games there is maybe 1 in a 100 downloads that actually plays the game at least a little bit. Add any sort of barrier like having to install a mod or onything like that and I would guess you are rather talking about 1 in a 1000.
And last but not least... open-sourcing it it the "right" tm thing to do
