What brand model of tripod.

Some tripods have a centre column that is configurable to allow it to be removed.

I know on some 190 model manfrottos, you can get a centre column that has a very short 50mm fixed upper shaft, and where the lower part of the shaft is comprised of a long tube section and the final lowest part is a end cap that screws onto the bottom of the centre shaft.
What this then does, is you unscrew the lower end cap, remove the central shaft, and you have no centre column.
Of course this then allows you to set the tripod up with the legs splayed along the ground.

Gitzo have a removable centre column, but the assembly needs to come apart completely, you need a hex key to do this and then you remount the top plate without the column in place.
System works, but looks a bit dodgy to me as there isn't much tube material on the upper plate for the tripod leg section to grip too!

I've seen some of those multi purpose manfrotto/gitzo/benro tripods that have an offset column that you can orientate from veritical to horizontal, but they look flimsy(especially for a proper macro tripod)..

I've just started getting more and more into macro shooting, and what was more than capable for most shooting situations, is completely useless for macro shooting.
Of course my preferred macro shooting style is to use as much available light as possible, and not have to rely on external speedlights and suchlike(yet!)