On Monday, 20 April 2015 21:05:35 UTC+1, wrote:
Instant on artificial horizons? Yes. Two choices.
The LXNav S80.
The Butterfly Vario.
Both are functioning at all times.
Both are 100% solid state and will not tumble.

The Vaulter - cheaper than either and both excellent and simple

http://wharingtonsmith.com/vaulter.html

Don't forget that none of these instruments are designed for that purpose - if you really need a AH you should buy an AH!