i am currently considering building a dual hdtv tuner pvr to record my favorite shows and convert them down to divx (not simulaneously). before i get too far into it, i was wondering if the following set up was plausible

tuner:
2x dvico fusion hdtv 5 lite recording analog cable and clear QAM hd from the same cable connection

computer (both allready on hand):
either an xp1800+/512mb@2700/fx5700ultra/7nif2
or a mdd dual 1ghz g4 with 512mb@2700 and a geforce 4 ti

software:
something free (probably linux pvr something)

either of these machines would be simply a recording box, not used for "live tv pausing" or anything like that, however it would need to be able to record 2 HD streams at the same time. i'd then take whatever file it pukes out and convert them down on my mac book pro.

at this point i'm wondering if either this is impossible with my current computers, or if there is a better and/or cheaper than 100$ hd tuner that i should look at.

i will happily admit that i'm very new to this, and hopefully i'm not delusional with my goals.

thanks