I'm a location sound recordist and need a camera for an upcoming project, I'm used to the the top end cameras set ups like Alexa, RED, and Sony but I'm after a lower level of camera and sort of out of that loop.

Must have....
1. Record to SD card/s.....NOT tape or Sony or Panasonic P2 cards or CF cards
2. Must have XLR audio inputs with phantom power.
3. Small size but must look 'Pro' enough and suitable for a air travel in hand luggage.
4. Need to able to record 4hrs+ continuous (if req.), 16:9 SD format (mains powering OK)
5. SDI output.
6. Capable of full HD recording (30 mins duration would be ok in this format)

Would be nice... But not critical
1. 4x tracks of audio
2. Some sort of o/p to enable a dual record to PC as a backup record.
3. Dual card slots.
4. Time lapse.
5. External DC input.

Not of high need..... and totally optional.
1. Time code
2. Interchangeable lenses.

Most of the need is sit down one on one interviews indoors for extended durations, mains powering, a basic lighting kit and a good audio kit would be available.
The end product will end up on private viewing on DVD or Internet, HD might get used as a second camera unit (but very rarely)

What makes / models might be suitable?

It sounds like the Panasonic AF100 fits the bill pretty well. The Canon XA10 would also do, and it's cheaper than the AF100.

The new XA25 is also a possibility with XLR, dual SD and HD-SDI.