tore apart too crapped rear wheels down to access the seal on the shimano (acera/stx-rc) freehub body. no go
one was a 7 speed, the other an 8 speed. both had the same seals but didn't match the XT. The XT has two pieces to it, a rubbery o-ring and then the brittle (plastic?) seal underneath which as I've shown has cracked when extracted, and the opening compared to the other freehub bodies is narrower. the two seals i pulled out of the other two hubs are one piece rubber (looks like the picture on the Park Tool site) and is thicker and won't fit into the narrower opening of the XT.
thought i could maybe use the 7 speed acera in place of the XT, but i don't think that will work either. the height isn't the same, the XT has a higher cassette offset at the base that sits into the deeper counter sunk area on the hub shell.
thinking i probably have to source something from a shimano pre-parallax rear freehub
XT freehub body on the left in the pics attached.