Harland Sharp has a variety of rocker shaft stands usually used for W-2 heads but can also be used for standard heads. Typically stands were used to raise and/or offest the rockers for clearance and proper geometry with bigger springs and/or taller valves. The problem is that you'll need to know how much your stands were milled, what finished height you need and if/how much they need to be offset!
I would think that they could sell the stands seperately, but don't know how much or what the easiest way would be to figure out what you need. I suppose you could send them an assembled head and perhaps the shafts & rockers you plan to use, but that just adds to the costs. Finding someone with stands to borrow for a trial fit would be nice.
Harland Sharp website
Are they all the same? I got a real nice set of CNC factory SB heads for cheap but the stands were milled off for who knows why 
