For Andy.

Andy, I don't know what random length of wire you are trying to tune, and 
for what frequency, but I have had extremely good luck with the atu in my 
elecraft k2, as well as the ldg z-100, and the atu in the kenwood ts2000.
I have a 90 foot wire configured as a half sloper, tying the shield of the 
coax to a 32 foot steel tower which is then grounded to an 8 foot ground rod.

Tunes well on all bands except 30 meters.  For that, I use a manual tuner 
behind the autotuner to give it just a little help.

I have also used a 44 foot doublet fed with 300 ohm twinlead and a 4-1 
balun with good results.

Please give a little more info about your antenna and requirements.
It seems strange that you can't find an atu for your needs.

73 and I'll try to help.