The rules as written are meant to be used with a hex map and counters. For demo purposes, or just sheer cool factor, miniatures can be used. I've been using Starmada minis from Brigade Models (link in the weblinks section). Using a non-hex delimited map, this requires some conversion.
For the purposes of minis, the following rules should be considered official.
1 hex = 1 inch(2.5cm)
Counters to show vector should be used. Bearing is shown by orienting the mini. Additionally, a counter or some other designation should be used for when a ship is rolled. Minis with hex bases should be used (as opposed to round/square bases) as this will aid in firing arcs and such.
I am looking into getting some minis custom sculpted and cast, probably resin. If/when this happens, they will be available for purchase through the regular channels.