Did some quick looking around (cause I've been saving loons for the 56TXi) and it seems like the 9300TX is quite a bit different than the 56TXi based on the limited information I found.
For example, there's no mention of iLink or USB on the 9300TX, which is an important issue for me. They weigh in differently as well: 9300TX @ 40 Lbs, 56TXi @ 45 Lbs. What happened to the five pounds?
The 56TXi has a 15 Lb power supply backed up by 27,000 uF and a heavy duty build, so maybe they trimmed back in this regard. It also looks like the 56TXi offers Pioneer's "Advanced MCACC" as opposed to just "MCACC" on the 9300TX. Guess we'll have to wait for more info from Pioneer.
Having said all that, I see the 9300TX is on sale right now at
http://www.vanns.com/shop/servlet/item/features/538184344 for 899.00 including shipping. That's about $600.00 less than the 56TXi.
Let's see ... that works out to just over $100/Lb savings. Not bad, eh?