From what i could read, the Northstar Transport uses the stock CDMPRo2 SPDIF and I2S out. they have given it a good power supply and robust casing.
As an alternative I have found Softone to be a very good CDM Pro2 based transport at less than 1/2 the cost..only problem is shipping is from japan. it only has RCA SPDIF out..if you speak to him he might customize an I2S out as well..
http://www.icl.co.jp/audio/english/m3-1.htm
