It’s not clear what the cost is for replacing the battery. Some ELT batteries are very expensive. But so is a vac pump – some $400 (for a good quality one) every few years.
Also removing the vac pump opens up the way to a B&C backup alternator.
The people who can’t do this are those with the KI256-driven King autopilot. Their options are
I flagged this up on the Vac system replacement thread but it seems a bit of re-branding has gone on !
I have just found that – you are right.
However Kelly don’t obviously mention that “6 hour” battery option, without which this is useless on a single alternator aircraft because if you get an alternator failure in IMC you need to look for an airport ASAP. And if the OAT is say -10C and there is IMC below, you are looking at a nice journey down with plenty of ice waiting for you 
this looks nice
http://www.sandia.aero/?q=node/80
When I installed my Aspens i went all electric and installed the RC Allen and it works fine. Be aware that there is an old version and a new version.. The last is much better and requires less depth.
The Sandia is being released now.. Looking at that price of usd 3.595.- I find it an encredible device.
