What are you wanting to use for the home automation remote and how do you control mythtv now? We need to know a bit more about your existing system and some details of what you are looking for.
On the simple end of things you can control mythtv with an IR remote with LIRC. You can make MythTV just another device on an IR remote and let the other devices control the HA stuff. Or I think you could make LIRC take in IR and issue commands to the HA system.
There are lots of more complex and/or more powerful things that could be done.
System:
I have 4 Ubuntu computers with either 32 / 64 bit with Mythtv added.
Currently I have three different remotes that use three different methods.
1. Lirc with a Snapstrem Firefly RF remote
2. Telnet with a Nokia N810 using Irreco
3. Android using phone with Mythmote
What I ideally would like to see:
Interface
A tablet that will have different customizable screens / pages for the different areas of control. An example: Audio / video screen (mythtv), Lighting screen, Specialized / custom screen (monitor cameras, HVAC,etc...) and more.
Have the flexibilty to continue to use the existing remote controls if possible but I understand that the Snap Stream remote would have limited capability due to the limited number of keys
HA software
The ability to do simple tasks ie turn on / off lights.
Create complex events ie trigger the lights on at dusk off at dawn, turn the coffee maker on at 6:05 during the week and then at 8:00 on weekends, adjust the blinds and lights depending on the time of day when I watch a video, etc...
The hardware to be mostly supported. I'm in the US and Zwave and Insteon (which I have but not married to it) seem to be the most widely used.
Now with all that said I understand that to get the idea package it may cost alot of money or I would need to be a programmer. I'm looking for something in the middle.
In my search I have tried several packages:
LMCE - has it pro's and con's, to deep to go into here
Misterhouse - I could never get installed properly, there wasn't an easy way for the average user to install it for linux
DomotiGa - doesn't look like it supports the interfacing ie tablets and just intergrated telnet
Openremote - I did get the android interface working on my phone for mythtv (using telnet) and the "single remote" looks promising but their hardware support in very lacking
Power home (windows) - I liked this package but there was no support to intergrate Mythtv
Hopefully this gets you started on what I would like to see and my capabilities.