anyone install Onan genset in front compartment?

Don't forget sound insulation. As per Onan spec, you should have insulation on all sides (perhaps the door) of the compartment, but not beneath the genset (so fuel dripping on it doesn't cause problems.) You should also have a vent in the front as well.

It also can't hurt to rubber shock mount everything (exhaust pipes, fuel and electric lines), and use the Onan resonator. This will quiet things down remarkably.