I've done Orchid macros with a 5x7 - my intended goal is platinum contact prints. I use a Nikon 120 Apo-Makro lens which fully covers 5x7 at infinity, and has plenty of depth of field even at close range. I did this work in the field (well, the Rawlings Conservatory up in Baltimore), using a lightweight Manfrotto carbon-fiber tripod, and had no issues with the tripod getting in the way. I'd much rather have the big ground glass to work on, especially when shooting macro work, so I can actually see what I'm focusing on.
Rembrandt, actually,I don't see any tradeoffs!
(1) In my estimation, there are zero DOF advantages for the smaller format.
(2) The LF camera, usually bellows focusing, allows the photographer to explore the 1:1 realm more flexibly... and go far beyond. Fine-tuning the effective magnification is trivial with a rail camera. It's much easier doing this with bellows than with extension tubes and such.
(3) Ground glass allows very precise composition, with a loupe. Way more precise than anything that can be done with an SLR viewfinder.
(4) Tilts allow us to do several things that cannot be done very easily in smaller formats. Yes, you can put a t&s lens or bellows on 35mm system, but it is far from being as flexible or comprehensive an approach.
(4b) Bear in mind that front to back sharpness, as a general strategy, has been done and done and done. But thinking more about all the options by which the focal plane can intersect something as wonderfully 3D as an orchid is an ongoing and enjoyable challenge.
(5) The tonality advantage of LF is especially important for floral macros. The tonality issue can be, I feel, as strong or even stronger than is the case with portraits.
(6) I don't find working with an LF camera/tripod to really be any harder than small format. Once you're on a tripod, you're on a tripod. At higher magnifications, you start to actually prefer the stability of the larger/bulkier system, and the low-impulse action of an LF leaf shutter is another benefit at that extreme. My favourite macro cameras are two big-beast systems frequently said to be unwieldy in the field: an rb67 and a cambo 8x10 monorail camera.
Now, having said all this, I definitely like using roll film for macro, because that allows me to work very quickly and bracket exposures. This can be a big issue if your subject is a delicate blossom that also requires some additional lighting.