Perhaps you could use a Terratec 1200 dual DVT-T instead of trying to find a PCIe networkcard that work in Linux.
Look at http://www.linuxtv.org/wiki/index.php/TerraTec_Cinergy_1200_DVB-T
This card cost 999kr in sweden which is about 110 euro. I don´t have one myself (have a nova-t 500) since I´m still evaluating how my core should be equipped.
I have some issues with my nova-t 500. I believe it is related to our dvb broadcasts here in sweden.
I´m in the same situation as you. Had to use a PCI gbit card (i use a ASUS M2VM-DH) since I could not find a PCIe card that worked in Linux.
Bought a ET1310 based card that have linux support according to the chip manufacturer, but it does not work in lmce0704
and not in mythbuntu 0710 which problably mean it won´t work out of the box with lmce0710 either.
After some investigation my conclusion is that many chip manufacturers support linux, but do not provide a driver available to other than oem partners.