Gotcha. OK, I don't have access to my shop right now so I can't build this to test it in Real Life (TM) but attached is what I would do.
There is a good tutorial on 555 calculations at in case you hadn't found those yet.
Anyway, the circuit I've attached uses the first half uses Ra = 130k and Rb = 500, and C = 1nF, for a frequency of:
f = 1.44 / ((Ra + 2Rb) * C)
f = 1.44 / ((130k + 1000) * 0.000001)
f = ~10.9kHz
So my math above gives ~11kHz. In the simulator it show closer to 10kHz. You did say it doesn't need to be exact.
The values might not look like a normal 555 astable, but that's because I wanted this one to have a very high duty cycle, in order to not affect the minimum off time of the following stage too much. (Note: this relates to a problem with the circuit--see below).
The second 555 takes the incoming pulses and produces output pulses from ~1us to ~50us. This is a problem (mentioned above), since the tutorials indicate that you don't want to try to get output pulses of less than ~10us out of them, or else risk having troubles with the 555 retriggering itself. At 10kHz your pulses occur every 0.1ms; 1% of 0.1ms is 1us. Too short. Note that I have found some forum posts indicating that 1us is OK--although right on the edge of the 555's capabilities.
So in summary: this might work. Common wisdom says the pulses needed are too short for a 555 to handle; some people appear to maintain that it's OK but be aware that it's potentially pushing things. Anyway, I'd just build the thing and scope it and see what I got.
If this can't be made to work, perhaps you can describe the problem you're trying to solve (instead of how you're trying to solve it) and we can help you come up with another solution.
Hope this helps,
Torben