I don't know the 803 model, but there is a tiny Sony Tektronix 308 analyzer. If it's a model you talked about then yes, it's a bit tricky to use. It's a very first data analyzer from Sony Tektronix, and the human interface is really counter intuitive.
Pleass take a look on a nice open source project:http://dangerousprototypes.com/docs/Open_Bench_Logic_Sniffer
I understand that it supports i2c and spi analysis.