New thought and realization here - Lookout!
For November's Chile/Argentina trip I took the Markins Q3 + GT2540, and it was manageable, but I also carried a 85 litre backpack at 27kg which included heavy rock climbing gear, plus 8kg Billingham camera shoulder bag. Of the suggestions above, the suggestion of the Cullman Magnsit 10 looked like a good choice on paper for size and $80 price. But since I already own the Markins Q3, the 125gm saved isn't worth a whole lot. Very shortly I'm off to India for 3 weeks, and this time my luggage is a 50 liter daypack plus the shoulder camera bag.
I just picked up a GT0541 off eBay, and although it is very light it looks like a winner. But the Markins Q3 dwarfs the tripod legs. Using the Q3 and with the center column down, the SLR comes to nearly chest height, and with the column all the way up the camera comes to nearly chin height (I'm 6'2").
Bling. I don't NEED a panning base!. If I'm satisfied to leave the column all the way down and the column clamp a little loose, then the column spins just as a panning base. I tried it and it's actually more precise than panning with the Q3.
Answer: RRS-25 ballhead, and leave the column down! Once again, less is more.
Cheers, Ralph