If your soundcard only has six inputs, there is no way to magically add any.

if i understand well the question... you have a emu 1820 right? it has 6 inputs line in, 2 xlr pres, 8 adat and a spidf right?
the emu 1820 is a sound card so u have the line ins and outs that are there!
if you want more buy a adat pre like the behringer ada 8000 or the m-audio octane

You can always use the ADAT optical with an external A2D converter for 8-more inputs.

FYI: E-mu is slated to release more product and options at the Jan NAMM show.