hello lee,
There are several bideirectional level translator that you may use:
1. If you want to use a translator for i2c or smbus then look at PCA9306 or PCA9547 if you need more channels.
i2c bidirection level translator can be used for general applications but make sure that your application does not requires you over 400kbps data rate
2. Try looking at MAX3372/MAX3393 if your data rate is in Mbps
3. or look at SN74AVC2T4/sn74avc4t245/sn74avc8t245 devices if you can supply direction input to the buffer. These devices are also very fast.
Regards