Well hopefully you will soon see some more - there should be a set of scenarios going up in the download section soon (I finally had the time to complete the maps this weekend - sorry they are still hand-drawn, but at least they are neater than the ones I used to run the thing through play tests!).
I've played quite a few future-set games over the years. Aside from Space Master, there have been Star Wars, Cyberspace, Cyberpunk, Paranoia, Serenity, Traveller, Babylon 5 and Dragonstar are the ones that spring to mind (have done a near-future Fireborn but it was like 2 years in the future, and also done Bubblegum Crisis which being anime is sort of future, but also probably doesn't count!). I don't think in any of them have been real space operas though.
The closest I've come to full on space opera have been a couple of games in Spacemaster - in one I played a Transhuman 5 Armsman revenging the murder of her family by Colosian agents (succeeded at level 36 by crashing a battlecruiser into their planet and then swanning off to become a galactic action movie megastar, principally on the strength of filming some of the combats along the way, computer enhancing them to remove armour, and hiring an awesome scriptwriter and director to string them together - "Such realistic effects!"), another where I played one of a pair of Kashmere agents in which I played a teep, and a slightly darker toned one in which I played an anarchist and wanted terrorist who got caught up in the League of Merchants. Most of the other games were more cyberpunky in flavour, and that is what I tried to go for in the scenarios.
Please don't be put off by the fact that the very initial germination of the idea was from the wonderful (!) movie Freejack (yes, the one with Mick Jagger and Emilio Estefez in) - the inspiration part was solely down to a very stratified and corporate society and the movie has no further impact on the setting! Future scenarios continuing from where they left off may yet take the players into space - it depends how my play test group want to go really, as I have two potential adventure pathways they could follow.