Sabayon sounds a lot like something I make for my drinks (i use the egg white for beverages, not the yolk). You can make a sabayon in an iSi whipper. Make certain you get the filmy-thin-sac-thing of the egg yolk before putting your sabayon mixture into an iSi whipper with nitrous oxide; if you leave it in, it can clog your whipper. For extra stability, I have used lecithin or soy protein (VersaWhip also comes to mind) to stabilize my egg-based foams with great success.
This may easily work the same for a sabayon as well. Regarding temperature, after you charge your whipper, perhaps you can place the whipper in appropriately warm or hot water. Keep in mind, high temperatures increase the amount of pressure in your whipper. Strain everything twice before putting your mix in a whipper.
This is the description I base my commentary on:
"A sabayon is made by beating egg yolks with a
liquid over simmering water until thickened and increased in volume. (
the liquid can be water, but champagne or wine is often
used for a savoury sabayon.) The sabayon must not get too hot during
cooking or it will become grainy: if it begins to feel warmer than body
temperature, remove the pan briefly from the heat, beating continuously,
until the mixture cools. Then return the pan to the heat and continue
cooking. Sabayon may be served warm or cold; a cold sabayon is beaten
off the heat until cooled.
Sabayons may be sweet or savoury. They may be served simply as a sauce,
often flavoured with
an alcohol, or they may form the base of some mousse mixtures.
They may also be used for sweet or savoury gratins.
Cornflour is sometimes added for stability."