The new Sony Xperia Tablet Z with a IP57 rating looks very promising. 10" tablets maybe a bit bulky for the bush (172x266mm - 10.47 x 6.77 inches) but only 495g. It compares reasonably well with the Nexus 7 and Nexus 10. Probably go on sale for around $650, so a little more expensive.
I like the IP57 rating. Screen density and resolution is less than the Nexus 10 but still good. Battery life looks good and external storage is a bonus.
Is it worth the price?