How about something like the AD654? The freq range is 0-500kHz. If it's not linear enough for you in the low range, and you can't get the performance you need by attenuating the input voltage, I suppose you can just put a divide by 10 on the output.

How about something like the AD654? The freq range is 0-500kHz. It's tunable with an RC pair, where \$ f=\frac {V}{10RC} \$ . If you can't get the range right, you can always pop a divide-by-10 on the output.