Don't think this is possible or necessarily desirable for a couple of reasons. First you have a misconception about the perceived advantages of keeping the input signal entirely in the "digital" domain. While its true that a firewire/DV input is digital the fact is that all DVD recorders that have firewire inputs are expecting to see video in DV digital format (and most of those are expecting to see DV transmitted from a camcorder device vs. a PC or other digital source of DV), they then have to take that DV digital input and transcode it to an MPEG2 video stream and either PCM or Dolby Digital Audio on-the-fly. This mpeg2 transcoding process takes place whether the input is digital DV or via the analog inputs. As such, there is not a significant advantage whether you are starting with an analog signal or a digital signal since the losses associated with recompression/transcoding typically overshadow any artifacts resulting from the analog/digital conversion circuits of the analog inputs. Bottom line, since transcoding takes place, there may only be a slight, typically visually imperceptible advantage to keeping the input all digital.
Second, I have never heard of a DV/Firewire to HDMI adaptor - I think the data transmission interface requirements are signifciantly different for the two types. While DVI to HDMI adaptors do exist, but that's to allow HDMI output to be used with a monitor that only has DVI input (a separate audio cable typically has to be used to provide the audio input in this case). In any event, even if such a beast did exist, it would likely be very expensive because for it to really work what you want to do you would have to take the mpeg2 output from your dish receiver via hdmi, transcode it to DV for the dvd recoreder to recognize the signal on the DV input and then the recorder would have to transcode that back to mpeg2. So in this case the two lossy digitial stream conversions would likely be very visually detrimental to the original video signal. In your case you are best off using the analog (s-video/component) outputs of your dish receiver and analog (s-video/component) inputs on the DVD recorder. Note also, that dvd recorders with component inputs are rare. Good luck.