Well, as far as I know 17/9 isn't possible. There is no such note as a "ninth" note. Even in an odd beat, you'd not have a ninth note. That's what I thought I was getting at in my post. As far as my knowledge spans, you can only use compound and simple meters. I'm not aware of any 5/10 or 4/15 time signatures.
True, but it could also be the following: 6/8 = x.x.x. or 6/8 = x.x..., etc. this kinda illustrates that different feels can be achieved using simple time signatures. You can also use longer patterns within even time sigs to achieve odd time effects: eg 4/4 = x..x..x..x.. x..x..x..x.. sounds like a 3 pattern, but is really four (resolved over two bars). By using patterns that overlap bars, but eventually resolve over a number of bars (no is the lowest common denominator - usually), you could simulate most times in a standard, readily understood time signature, rather than confusing the life out of those who are performing your compositions!
Yeh, there's some really cool stuff in 7/8, 9/8 (not the 3 x dotted notes version!!!), and 13/8 by my favourite band erm, Rush (no prizes given!)
13/8 can also be found on "Flood" by Tool. x . . x . . x . . x . x . By just breaking the bar down into 2's and 3's, you can get some nice rhythms going on. Weird 5/4 by the Kinison: x . x . . x . . x . It sounds easy when you hear it, but that accentuation is rock hard.