If you really mean ULF (i.e. bigger than 8x10"), then there is a real difficulty in finding a worthwhile tripod that you can carry any distance. I personally use 4x5" to 8x10", outside with my 4x5" Crown Graphic I find a Manfrotto 055 tripod is good if used with care, while in the studio a Manfrotto 058 handles just about anything. As the Manfrotto 058 has the "triaut" mechanism (all 3 legs controlled by a ring under the tripod head), I do not like to use it in dirty conditions (it copes OK but it needs a wash down and spray with WD40 afterwards), so I keep an old De Vere tripod as a standby for a heavy support for outdoors.