Sorry, two of your ideas will not work;
- PCIe support requires specialized transceivers that do not exist on these boards.
- OpenCL support is specific to a small range of latest-generation boards.
But 1GbE might be ok - at least the kits support that.
What is the data rate you need to achieve to your host PC?
Cypress just released their EZ-USB FX3 kit
http://www.cypress.com/?rid=99916 This $49 kit has a USB 3.0 controller on it, and should provide >100MB/s transfers (depending on your PC).
The kit can be interfaced to the HSMC connector on the DE2-115 via an HSMC adapter board
http://www.cypress.com/?rid=99922 which is also $49 (although when I ordered my kit, I just requested this board, and they sent it to me).
The kit already comes with Altera interface examples. I haven't tested them yet, but I will, so if you decide to go this route and get stuck, you can ask for advice.
Cheers,
Dave