@Darren, if you mean in terms of something realtime with actual 3D space combat like elite has, I agree we need a game, though I'll say that for something turn based the smugglers series does pretty well.
@DracoSelene89. You can throw money at me if you like, but I'm not actually a developer, I'm promotion/publicity/hassle developers to make stuff accessible guy.
In truth though the sales metric with audiogames is a little different, since people tend to respect good design in the community a lot better, however just by virtue of available resources and who has time to do what, since your talking about indi developers who have to programm mostly from scrach with no convenient tools, your still looking at something relatively minimal, albeit audiogames have very much improved.
On the racing idea I can't really help as racing games have never been my thing, though if your a fan of vehicle sims I'd also recommend zero site, and good old gma tank commander.
For the ship idea, well you could get the idea of walking round your own ship and even saying orders to the computer with some of the space muds, albeit the only space mud I've had actual success with is cosmic rage.
Empire mud I confess I never got on with myself, partly because I found the staff less than helpful, but there are a lot of good muds out there, albeit the only other mud which had actual strategical empire building I know of was Wayfare1444, which sadly shut down recently (a shame it was a good game with great potential).
I'd recommend not using telnet for muds for one very simple reason. Namely with muds you need to be aware of the text that comes in as soon as humanly possible in order to react to it.
This is where mud clients that interact with a screen reader directly help you.
vipmud is the client I prefer, though people have also had success with musclient.
If you ever fancy alteraeon I would! recommend the mushZ custom client which is based on mushclient, just because it virtually converts alteraeon into an audiogame, ie, a full on audio mmorpg which is a good thing indeed.
With our dreaming and singing, Ceaseless and sorrowless we! The glory about us clinging Of the glorious futures we see,
Our souls with high music ringing; O men! It must ever be
That we dwell in our dreaming and singing, A little apart from ye. (Arthur O'Shaughnessy 1873.)