As a few others would be interested in, there is a utility application from 1geek1tool folks called Guidetool http://1geek1tool.com/guidetool that allows you to map and merge multiple tuners to mce EPG. I only have the Hava so am not sure if this will work with let's say a tuner card and a hava or if the same problem will occur with hava changing channels the same as the tuner card.
But this software is free if the hava folks or someone out there wants to test... might allow you to have 2 hava's for one mce. May have to get their dvblink tv source s/w but not sure.