I hadn't seen LinVDR before. Do you know what PVR they use? Is it also Myth based? I tried to read the docs, but mein deutsche ist nicht so gut.
I just posted a long response about converting/merging here: http://plutohome.com/support/phpbb2/viewtopic.php?t=103
Regarding the DVB-Card, who makes it? Are the drivers included in the Linux kernel? If they are built separately, what we may be able to do is either (a) add the package to our database if it exists somewhere as a Debian package, or if it does not (b) add it to our automated build system so that it compiles and builds a Debian package for it. Either way, once it's in our database it will just be a checkbox on the Media Director's wizard page like the other capture cards we support: IVTV and Blackbird.
The easiest way to install Pluto is with a kick-start CD that, like LinVDR, basically wipes out the hard drive and starts from scratch. However, it only requires 1 dedicated PC for the whole house, and it exposes a network boot for all the others. So, if you put the kick-start CD in a new computer, that becomes dedicated, and then it will expose a network boot for your existing LinVDR. You just choose on the remote control (ie Orbiter) if you want to do a regular hard drive boot (like you do now), or a network boot into a Pluto Media Director. So it's very easy for them to co-exist.