[jason taylor]

From the narrative(I make no claims for the engineering POV) point of view total invisibility is unnecessary and not necessarily desirable. Better is a sort of limited stealth allowing the hunter and the hunted to parse numerous factors in calculating one another's whereabouts. If invisibility is possible fighting is impossible. If however limited stealth is possible we can have the pleasure of multi hour or even multi day fights like Star trek Balence of Terror, or the second episode of Andromeda.

To do this there are several ways that might come to might. One is a sort of thermal damper that is capable of concealing heat up to a certain point; this might require it to be flushed out every few hours to cool it and the flushing will reveal the ship. Far from being a bug, this is a feature; it allows the rival captains a factor to calculate.