PCI expansion modules for Analog interface cards

I need to connect 100 FXS lines to asterisk server . I m planing to use 24 /16 / 8 analog interface card combination. issue is I m run out of PCI slots . I feel the solution is going for PCI expansion chassis. If you have any experience on PCI expansion chassis with asterisk please let me know. Is there any possibilities if IRQ issues or performance.